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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<!-- Generated by HsColour, http://code.haskell.org/~malcolm/hscolour/ -->
<title>src/MonadLib.hs</title>
<link type='text/css' rel='stylesheet' href='hscolour.css' />
</head>
<body>
<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP, MultiParamTypeClasses, FunctionalDependencies,
<a name="line-2"></a>             UndecidableInstances, FlexibleInstances #-}</span>
<a name="line-3"></a><span class='hs-comment'>{-# LANGUAGE Rank2Types #-}</span>
<a name="line-4"></a><span class='hs-comment'>{-# LANGUAGE ScopedTypeVariables #-}</span>
<a name="line-5"></a><span class='hs-comment'>{-# LANGUAGE Trustworthy #-}</span>
<a name="line-6"></a><span class='hs-comment'>{-| This library provides a collection of monad transformers that
<a name="line-7"></a>    can be combined to produce various monads.
<a name="line-8"></a>-}</span>
<a name="line-9"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>MonadLib</span> <span class='hs-layout'>(</span>
<a name="line-10"></a>  <span class='hs-comment'>-- * Types</span>
<a name="line-11"></a>  <span class='hs-comment'>-- $Types</span>
<a name="line-12"></a>  <span class='hs-conid'>Id</span><span class='hs-layout'>,</span> <span class='hs-conid'>Lift</span><span class='hs-layout'>,</span> <span class='hs-conid'>IdT</span><span class='hs-layout'>,</span> <span class='hs-conid'>ReaderT</span><span class='hs-layout'>,</span> <span class='hs-conid'>WriterT</span><span class='hs-layout'>,</span>
<a name="line-13"></a>  <span class='hs-conid'>StateT</span><span class='hs-layout'>,</span>
<a name="line-14"></a>  <span class='hs-conid'>ExceptionT</span><span class='hs-layout'>,</span>
<a name="line-15"></a>  <span class='hs-comment'>--</span>
<a name="line-16"></a>  <span class='hs-comment'>-- $WriterM_ExceptionT</span>
<a name="line-17"></a>  <span class='hs-conid'>ChoiceT</span><span class='hs-layout'>,</span> <span class='hs-conid'>ContT</span><span class='hs-layout'>,</span>
<a name="line-18"></a>
<a name="line-19"></a>  <span class='hs-comment'>-- * Lifting</span>
<a name="line-20"></a>  <span class='hs-comment'>-- $Lifting</span>
<a name="line-21"></a>  <span class='hs-conid'>MonadT</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>BaseM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-22"></a>
<a name="line-23"></a>  <span class='hs-comment'>-- * Effect Classes</span>
<a name="line-24"></a>  <span class='hs-comment'>-- $Effects</span>
<a name="line-25"></a>  <span class='hs-conid'>ReaderM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>WriterM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>StateM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>ExceptionM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>ContM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>AbortM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-26"></a>  <span class='hs-conid'>Label</span><span class='hs-layout'>,</span> <span class='hs-varid'>labelCC</span><span class='hs-layout'>,</span> <span class='hs-varid'>labelCC_</span><span class='hs-layout'>,</span> <span class='hs-varid'>jump</span><span class='hs-layout'>,</span> <span class='hs-varid'>labelC</span><span class='hs-layout'>,</span> <span class='hs-varid'>callCC</span><span class='hs-layout'>,</span>
<a name="line-27"></a>
<a name="line-28"></a>  <span class='hs-comment'>-- * Execution</span>
<a name="line-29"></a>
<a name="line-30"></a>  <span class='hs-comment'>-- ** Eliminating Effects</span>
<a name="line-31"></a>  <span class='hs-comment'>-- $Execution</span>
<a name="line-32"></a>  <span class='hs-varid'>runId</span><span class='hs-layout'>,</span> <span class='hs-varid'>runLift</span><span class='hs-layout'>,</span>
<a name="line-33"></a>  <span class='hs-varid'>runIdT</span><span class='hs-layout'>,</span> <span class='hs-varid'>runReaderT</span><span class='hs-layout'>,</span> <span class='hs-varid'>runWriterT</span><span class='hs-layout'>,</span>
<a name="line-34"></a>  <span class='hs-varid'>runStateT</span><span class='hs-layout'>,</span> <span class='hs-varid'>runExceptionT</span><span class='hs-layout'>,</span> <span class='hs-varid'>runContT</span><span class='hs-layout'>,</span>
<a name="line-35"></a>  <span class='hs-varid'>runChoiceT</span><span class='hs-layout'>,</span> <span class='hs-varid'>findOne</span><span class='hs-layout'>,</span> <span class='hs-varid'>findAll</span><span class='hs-layout'>,</span>
<a name="line-36"></a>  <span class='hs-conid'>RunM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-37"></a>
<a name="line-38"></a>  <span class='hs-comment'>-- ** Nested Execution</span>
<a name="line-39"></a>  <span class='hs-comment'>-- $Nested_Exec</span>
<a name="line-40"></a>  <span class='hs-conid'>RunReaderM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>RunWriterM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>RunExceptionM</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-41"></a>
<a name="line-42"></a>  <span class='hs-comment'>-- * Utility functions</span>
<a name="line-43"></a>  <span class='hs-varid'>asks</span><span class='hs-layout'>,</span> <span class='hs-varid'>puts</span><span class='hs-layout'>,</span> <span class='hs-varid'>sets</span><span class='hs-layout'>,</span> <span class='hs-varid'>sets_</span><span class='hs-layout'>,</span> <span class='hs-varid'>raises</span><span class='hs-layout'>,</span>
<a name="line-44"></a>  <span class='hs-varid'>mapReader</span><span class='hs-layout'>,</span> <span class='hs-varid'>mapWriter</span><span class='hs-layout'>,</span> <span class='hs-varid'>mapException</span><span class='hs-layout'>,</span>
<a name="line-45"></a>  <span class='hs-varid'>handle</span><span class='hs-layout'>,</span>
<a name="line-46"></a>
<a name="line-47"></a>  <span class='hs-comment'>-- * Miscellaneous</span>
<a name="line-48"></a>  <span class='hs-varid'>version</span><span class='hs-layout'>,</span>
<a name="line-49"></a>  <span class='hs-keyword'>module</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span>
<a name="line-50"></a><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-51"></a>
<a name="line-52"></a>
<a name="line-53"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Applicative</span>
<a name="line-54"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span>
<a name="line-55"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Fix</span>
<a name="line-56"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>ST</span> <span class='hs-layout'>(</span><span class='hs-conid'>ST</span><span class='hs-layout'>)</span>
<a name="line-57"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Exception</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-varid'>throwIO</span><span class='hs-layout'>,</span><span class='hs-varid'>try</span><span class='hs-layout'>)</span>
<a name="line-58"></a><span class='hs-cpp'>#ifdef USE_BASE3</span>
<a name="line-59"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Exception</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>Exception</span><span class='hs-layout'>)</span>
<a name="line-60"></a><span class='hs-cpp'>#else</span>
<a name="line-61"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Exception</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>SomeException</span><span class='hs-layout'>)</span>
<a name="line-62"></a><span class='hs-cpp'>#endif</span>
<a name="line-63"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Exit</span><span class='hs-layout'>(</span><span class='hs-conid'>ExitCode</span><span class='hs-layout'>,</span><span class='hs-varid'>exitWith</span><span class='hs-layout'>)</span>
<a name="line-64"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Monoid</span>
<a name="line-65"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Prelude</span> <span class='hs-varid'>hiding</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ordering</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-66"></a>
<a name="line-67"></a><a name="version"></a><span class='hs-comment'>-- | The current version of the library.</span>
<a name="line-68"></a><span class='hs-definition'>version</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</span><span class='hs-conid'>Int</span><span class='hs-layout'>)</span>
<a name="line-69"></a><span class='hs-definition'>version</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-num'>3</span><span class='hs-layout'>,</span><span class='hs-num'>5</span><span class='hs-layout'>,</span><span class='hs-num'>2</span><span class='hs-layout'>)</span>
<a name="line-70"></a>
<a name="line-71"></a>
<a name="line-72"></a><span class='hs-comment'>-- $Types</span>
<a name="line-73"></a><span class='hs-comment'>--</span>
<a name="line-74"></a><span class='hs-comment'>-- The following types define the representations of the</span>
<a name="line-75"></a><span class='hs-comment'>-- computation types supported by the library.</span>
<a name="line-76"></a><span class='hs-comment'>-- Each type adds support for a different effect.</span>
<a name="line-77"></a>
<a name="line-78"></a><a name="Id"></a><span class='hs-comment'>-- | Computations with no effects.</span>
<a name="line-79"></a><a name="Id"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>Id</span> <span class='hs-varid'>a</span>              <span class='hs-keyglyph'>=</span> <span class='hs-conid'>I</span> <span class='hs-varid'>a</span>
<a name="line-80"></a>
<a name="line-81"></a><a name="Lift"></a><span class='hs-comment'>-- | Computation with no effects (strict).</span>
<a name="line-82"></a><a name="Lift"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>Lift</span> <span class='hs-varid'>a</span>               <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>a</span>
<a name="line-83"></a>
<a name="line-84"></a><a name="IdT"></a><span class='hs-comment'>-- | Adds no new features.  Useful as a placeholder.</span>
<a name="line-85"></a><a name="IdT"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>           <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-86"></a>
<a name="line-87"></a><a name="ReaderT"></a><span class='hs-comment'>-- | Add support for propagating a context of type @i@.</span>
<a name="line-88"></a><a name="ReaderT"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>     <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-89"></a>
<a name="line-90"></a><a name="WriterT"></a><span class='hs-comment'>-- | Add support for collecting values of type @i@.</span>
<a name="line-91"></a><a name="WriterT"></a><span class='hs-comment'>-- The type @i@ should be a monoid, whose unit is used to represent</span>
<a name="line-92"></a><a name="WriterT"></a><span class='hs-comment'>-- a lack of a value, and whose binary operation is used to combine</span>
<a name="line-93"></a><a name="WriterT"></a><span class='hs-comment'>-- multiple values.</span>
<a name="line-94"></a><a name="WriterT"></a><span class='hs-comment'>-- This transformer is strict in its output component.</span>
<a name="line-95"></a><a name="WriterT"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-layout'>{</span> <span class='hs-varid'>unW</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-96"></a><a name="P"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-varop'>!</span><span class='hs-varid'>i</span>
<a name="line-97"></a>
<a name="line-98"></a><a name="StateT"></a><span class='hs-comment'>-- | Add support for threading state of type @i@.</span>
<a name="line-99"></a><a name="StateT"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>StateT</span>     <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>i</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-100"></a>
<a name="line-101"></a><a name="ExceptionT"></a><span class='hs-comment'>-- | Add support for exceptions of type @i@.</span>
<a name="line-102"></a><a name="ExceptionT"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-varid'>i</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-103"></a>
<a name="line-104"></a><a name="ChoiceT"></a><span class='hs-comment'>-- | Add support for multiple answers.</span>
<a name="line-105"></a><a name="ChoiceT"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>          <span class='hs-keyglyph'>=</span> <span class='hs-conid'>NoAnswer</span>
<a name="line-106"></a>                          <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Answer</span> <span class='hs-varid'>a</span>
<a name="line-107"></a>                          <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Choice</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-108"></a>                          <span class='hs-keyglyph'>|</span> <span class='hs-conid'>ChoiceEff</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-109"></a>
<a name="line-110"></a><a name="ContT"></a><span class='hs-comment'>-- | Add support for continuations within a prompt of type @i@.</span>
<a name="line-111"></a><a name="ContT"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-112"></a>
<a name="line-113"></a><span class='hs-comment'>-- $Execution</span>
<a name="line-114"></a><span class='hs-comment'>--</span>
<a name="line-115"></a><span class='hs-comment'>-- The following functions eliminate the outermost effect</span>
<a name="line-116"></a><span class='hs-comment'>-- of a computation by translating a computation into an</span>
<a name="line-117"></a><span class='hs-comment'>-- equivalent computation in the underlying monad.</span>
<a name="line-118"></a><span class='hs-comment'>-- (The exceptions are 'Id' and 'Lift' which are not transformers</span>
<a name="line-119"></a><span class='hs-comment'>-- but ordinary monads and so, their run operations simply</span>
<a name="line-120"></a><span class='hs-comment'>-- eliminate the monad.)</span>
<a name="line-121"></a>
<a name="line-122"></a>
<a name="line-123"></a><a name="runId"></a><span class='hs-comment'>-- | Get the result of a pure computation.</span>
<a name="line-124"></a><span class='hs-definition'>runId</span>         <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Id</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-125"></a><span class='hs-definition'>runId</span> <span class='hs-layout'>(</span><span class='hs-conid'>I</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span>
<a name="line-126"></a>
<a name="line-127"></a><a name="runLift"></a><span class='hs-comment'>-- | Get the result of a pure strict computation.</span>
<a name="line-128"></a><span class='hs-definition'>runLift</span>       <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Lift</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-129"></a><span class='hs-definition'>runLift</span> <span class='hs-layout'>(</span><span class='hs-conid'>L</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span>
<a name="line-130"></a>
<a name="line-131"></a>
<a name="line-132"></a><a name="runIdT"></a><span class='hs-comment'>-- | Remove an identity layer.</span>
<a name="line-133"></a><span class='hs-definition'>runIdT</span>        <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-134"></a><span class='hs-definition'>runIdT</span> <span class='hs-layout'>(</span><span class='hs-conid'>IT</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span>
<a name="line-135"></a>
<a name="line-136"></a><a name="runReaderT"></a><span class='hs-comment'>-- | Execute a reader computation in the given context.</span>
<a name="line-137"></a><span class='hs-definition'>runReaderT</span>    <span class='hs-keyglyph'>::</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-138"></a><span class='hs-definition'>runReaderT</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>R</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-139"></a>
<a name="line-140"></a><a name="runWriterT"></a><span class='hs-comment'>-- | Execute a writer computation.</span>
<a name="line-141"></a><span class='hs-comment'>-- Returns the result and the collected output.</span>
<a name="line-142"></a><span class='hs-definition'>runWriterT</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-143"></a><span class='hs-definition'>runWriterT</span> <span class='hs-layout'>(</span><span class='hs-conid'>W</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span> <span class='hs-varid'>to_pair</span> <span class='hs-varid'>m</span>
<a name="line-144"></a>  <span class='hs-keyword'>where</span> <span class='hs-varid'>to_pair</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-145"></a>
<a name="line-146"></a><a name="runStateT"></a><span class='hs-comment'>-- | Execute a stateful computation in the given initial state.</span>
<a name="line-147"></a><span class='hs-comment'>-- The second component of the result is the final state.</span>
<a name="line-148"></a><span class='hs-definition'>runStateT</span>     <span class='hs-keyglyph'>::</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-149"></a><span class='hs-definition'>runStateT</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-150"></a>
<a name="line-151"></a><a name="runExceptionT"></a><span class='hs-comment'>-- | Execute a computation with exceptions.</span>
<a name="line-152"></a><span class='hs-comment'>-- Successful results are tagged with 'Right',</span>
<a name="line-153"></a><span class='hs-comment'>-- exceptional results are tagged with 'Left'.</span>
<a name="line-154"></a><span class='hs-definition'>runExceptionT</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-varid'>i</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-155"></a><span class='hs-definition'>runExceptionT</span> <span class='hs-layout'>(</span><span class='hs-conid'>X</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>m</span>
<a name="line-156"></a>
<a name="line-157"></a><a name="runChoiceT"></a><span class='hs-comment'>-- | Execute a computation that may return multiple answers.</span>
<a name="line-158"></a><span class='hs-comment'>-- The resulting computation returns 'Nothing'</span>
<a name="line-159"></a><span class='hs-comment'>-- if no answers were found, or @Just (answer,new_comp)@,</span>
<a name="line-160"></a><span class='hs-comment'>-- where @answer@ is an answer, and @new_comp@ is a computation</span>
<a name="line-161"></a><span class='hs-comment'>-- that may produce more answers.</span>
<a name="line-162"></a><span class='hs-comment'>-- The search is depth-first and left-biased with respect to the</span>
<a name="line-163"></a><span class='hs-comment'>-- 'mplus' operation.</span>
<a name="line-164"></a><span class='hs-definition'>runChoiceT</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-165"></a><span class='hs-definition'>runChoiceT</span> <span class='hs-layout'>(</span><span class='hs-conid'>Answer</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-conid'>NoAnswer</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-166"></a><span class='hs-definition'>runChoiceT</span> <span class='hs-conid'>NoAnswer</span>       <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>Nothing</span>
<a name="line-167"></a><span class='hs-definition'>runChoiceT</span> <span class='hs-layout'>(</span><span class='hs-conid'>Choice</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>   <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>runChoiceT</span> <span class='hs-varid'>l</span>
<a name="line-168"></a>                               <span class='hs-keyword'>case</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>of</span>
<a name="line-169"></a>                                 <span class='hs-conid'>Nothing</span>      <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runChoiceT</span> <span class='hs-varid'>r</span>
<a name="line-170"></a>                                 <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>l1</span><span class='hs-layout'>)</span>  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-conid'>Choice</span> <span class='hs-varid'>l1</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-171"></a><span class='hs-definition'>runChoiceT</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceEff</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runChoiceT</span> <span class='hs-varop'>=&lt;&lt;</span> <span class='hs-varid'>m</span>
<a name="line-172"></a>
<a name="line-173"></a><a name="findOne"></a><span class='hs-comment'>-- | Execute a computation that may return multiple answers,</span>
<a name="line-174"></a><span class='hs-comment'>-- returning at most one answer.</span>
<a name="line-175"></a><span class='hs-definition'>findOne</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-176"></a><span class='hs-definition'>findOne</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>fst</span> <span class='hs-varop'>`liftM`</span> <span class='hs-varid'>runChoiceT</span> <span class='hs-varid'>m</span>
<a name="line-177"></a>
<a name="line-178"></a><a name="findAll"></a><span class='hs-comment'>-- | Execute a computation that may return multiple answers,</span>
<a name="line-179"></a><span class='hs-comment'>-- collecting all possible answers.</span>
<a name="line-180"></a><span class='hs-definition'>findAll</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span>
<a name="line-181"></a><span class='hs-definition'>findAll</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>all_res</span> <span class='hs-varop'>=&lt;&lt;</span> <span class='hs-varid'>runChoiceT</span> <span class='hs-varid'>m</span>
<a name="line-182"></a>  <span class='hs-keyword'>where</span> <span class='hs-varid'>all_res</span> <span class='hs-conid'>Nothing</span>       <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-183"></a>        <span class='hs-varid'>all_res</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-keyword'>as</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-conop'>:</span><span class='hs-layout'>)</span> <span class='hs-varop'>`liftM`</span> <span class='hs-varid'>findAll</span> <span class='hs-keyword'>as</span>
<a name="line-184"></a>
<a name="line-185"></a><a name="runContT"></a><span class='hs-comment'>-- | Execute a computation with the given continuation.</span>
<a name="line-186"></a><span class='hs-definition'>runContT</span>      <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-187"></a><span class='hs-definition'>runContT</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>C</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-188"></a>
<a name="line-189"></a>
<a name="line-190"></a><a name="RunM"></a><span class='hs-comment'>-- | Generalized running.</span>
<a name="line-191"></a><a name="RunM"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>where</span>
<a name="line-192"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>r</span>
<a name="line-193"></a>
<a name="line-194"></a><a name="instance%20RunM%20Id%20a%20a"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-conid'>Id</span> <span class='hs-varid'>a</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>where</span>
<a name="line-195"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runId</span>
<a name="line-196"></a>
<a name="line-197"></a><a name="instance%20RunM%20Lift%20a%20a"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-conid'>Lift</span> <span class='hs-varid'>a</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>where</span>
<a name="line-198"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runLift</span>
<a name="line-199"></a>
<a name="line-200"></a><a name="instance%20RunM%20IO%20a%20(IO%20a)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-conid'>IO</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-201"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-202"></a>
<a name="line-203"></a><a name="instance%20RunM%20(IdT%20m)%20a%20r"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>where</span>
<a name="line-204"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runM</span> <span class='hs-varop'>.</span> <span class='hs-varid'>runIdT</span>
<a name="line-205"></a>
<a name="line-206"></a><a name="instance%20RunM%20(ReaderT%20i%20m)%20a%20(i%20-%3e%20r)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-207"></a>  <span class='hs-varid'>runM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runM</span> <span class='hs-layout'>(</span><span class='hs-varid'>runReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-208"></a>
<a name="line-209"></a><a name="instance%20RunM%20(WriterT%20i%20m)%20a%20r"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>,</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>where</span>
<a name="line-210"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runM</span> <span class='hs-varop'>.</span> <span class='hs-varid'>runWriterT</span>
<a name="line-211"></a>
<a name="line-212"></a><a name="instance%20RunM%20(StateT%20i%20m)%20a%20(i%20-%3e%20r)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-213"></a>  <span class='hs-varid'>runM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runM</span> <span class='hs-layout'>(</span><span class='hs-varid'>runStateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-214"></a>
<a name="line-215"></a><a name="instance%20RunM%20(ExceptionT%20i%20m)%20a%20r"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-varid'>i</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>where</span>
<a name="line-216"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runM</span> <span class='hs-varop'>.</span> <span class='hs-varid'>runExceptionT</span>
<a name="line-217"></a>
<a name="line-218"></a><a name="instance%20RunM%20(ContT%20i%20m)%20a%20((a%20-%3e%20m%20i)%20-%3e%20r)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-219"></a>  <span class='hs-varid'>runM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runM</span> <span class='hs-layout'>(</span><span class='hs-varid'>runContT</span> <span class='hs-varid'>k</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-220"></a>
<a name="line-221"></a><a name="instance%20RunM%20(ChoiceT%20m)%20a%20r"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunM</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>where</span>
<a name="line-222"></a>  <span class='hs-varid'>runM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runM</span> <span class='hs-varop'>.</span> <span class='hs-varid'>runChoiceT</span>
<a name="line-223"></a>
<a name="line-224"></a>
<a name="line-225"></a><span class='hs-comment'>-- $Lifting</span>
<a name="line-226"></a><span class='hs-comment'>--</span>
<a name="line-227"></a><span class='hs-comment'>-- The following operations allow us to promote computations</span>
<a name="line-228"></a><span class='hs-comment'>-- in the underlying monad to computations that support an extra</span>
<a name="line-229"></a><span class='hs-comment'>-- effect.  Computations defined in this way do not make use of</span>
<a name="line-230"></a><span class='hs-comment'>-- the new effect but can be combined with other operations that</span>
<a name="line-231"></a><span class='hs-comment'>-- utilize the effect.</span>
<a name="line-232"></a>
<a name="line-233"></a>
<a name="line-234"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span> <span class='hs-keyword'>where</span>
<a name="line-235"></a>  <span class='hs-comment'>-- | Promote a computation from the underlying monad.</span>
<a name="line-236"></a>  <span class='hs-varid'>lift</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-237"></a>
<a name="line-238"></a><a name="instance%20MonadT%20IdT"></a><span class='hs-comment'>-- Notes:</span>
<a name="line-239"></a><a name="instance%20MonadT%20IdT"></a><span class='hs-comment'>--   * It is interesting to note that these use something the resembles</span>
<a name="line-240"></a><a name="instance%20MonadT%20IdT"></a><span class='hs-comment'>--     the non-transformer 'return's.</span>
<a name="line-241"></a><a name="instance%20MonadT%20IdT"></a><span class='hs-comment'>--   * These are more general then the lift in the MonadT class because</span>
<a name="line-242"></a><a name="instance%20MonadT%20IdT"></a><span class='hs-comment'>--     most of them can lift arbitrary functors (some, even arbitrary type ctrs)</span>
<a name="line-243"></a><a name="instance%20MonadT%20IdT"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadT</span> <span class='hs-conid'>IdT</span>            <span class='hs-keyword'>where</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-varid'>m</span>
<a name="line-244"></a><a name="instance%20MonadT%20(ReaderT%20i)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadT</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span>    <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-245"></a><a name="instance%20MonadT%20(StateT%20i)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadT</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span>     <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>liftM</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-246"></a><a name="instance%20MonadT%20(WriterT%20i)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-247"></a>      <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadT</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>    <span class='hs-keyword'>where</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-248"></a><a name="instance%20MonadT%20(ExceptionT%20i)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadT</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-conid'>Right</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-249"></a><a name="instance%20MonadT%20ChoiceT"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadT</span> <span class='hs-conid'>ChoiceT</span>        <span class='hs-keyword'>where</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>ChoiceEff</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-conid'>Answer</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-250"></a><a name="instance%20MonadT%20(ContT%20i)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadT</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span>      <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>
<a name="line-251"></a>
<a name="line-252"></a>
<a name="line-253"></a><span class='hs-comment'>-- Definitions for some of the methods that are the same for all transformers</span>
<a name="line-254"></a>
<a name="line-255"></a><a name="t_inBase"></a><span class='hs-definition'>t_inBase</span>   <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>n</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-256"></a><span class='hs-definition'>t_inBase</span> <span class='hs-varid'>m</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>inBase</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-257"></a>
<a name="line-258"></a><a name="t_return"></a><span class='hs-definition'>t_return</span>   <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-259"></a><span class='hs-definition'>t_return</span> <span class='hs-varid'>x</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-260"></a>
<a name="line-261"></a><a name="t_fail"></a><span class='hs-definition'>t_fail</span>     <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-262"></a><span class='hs-definition'>t_fail</span> <span class='hs-varid'>x</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>fail</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-263"></a>
<a name="line-264"></a><a name="t_mzero"></a><span class='hs-definition'>t_mzero</span>    <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-265"></a><span class='hs-definition'>t_mzero</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>mzero</span>
<a name="line-266"></a>
<a name="line-267"></a><a name="t_ask"></a><span class='hs-definition'>t_ask</span>      <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-268"></a><span class='hs-definition'>t_ask</span>       <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>ask</span>
<a name="line-269"></a>
<a name="line-270"></a><a name="t_put"></a><span class='hs-definition'>t_put</span>      <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-271"></a><span class='hs-definition'>t_put</span> <span class='hs-varid'>x</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>put</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-272"></a>
<a name="line-273"></a><a name="t_get"></a><span class='hs-definition'>t_get</span>      <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-274"></a><span class='hs-definition'>t_get</span>       <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-varid'>get</span>
<a name="line-275"></a>
<a name="line-276"></a><a name="t_set"></a><span class='hs-definition'>t_set</span>      <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-277"></a><span class='hs-definition'>t_set</span> <span class='hs-varid'>i</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>set</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-278"></a>
<a name="line-279"></a><a name="t_raise"></a><span class='hs-definition'>t_raise</span>    <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-280"></a><span class='hs-definition'>t_raise</span> <span class='hs-varid'>i</span>   <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>raise</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-281"></a>
<a name="line-282"></a><a name="t_abort"></a><span class='hs-definition'>t_abort</span>    <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-283"></a><span class='hs-definition'>t_abort</span> <span class='hs-varid'>i</span>   <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>abort</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-284"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-285"></a>
<a name="line-286"></a>
<a name="line-287"></a><a name="BaseM"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>n</span> <span class='hs-keyword'>where</span>
<a name="line-288"></a>  <span class='hs-comment'>-- | Promote a computation from the base monad.</span>
<a name="line-289"></a>  <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>n</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-290"></a>
<a name="line-291"></a><a name="instance%20BaseM%20IO%20IO"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>BaseM</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>IO</span>         <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-292"></a><a name="instance%20BaseM%20Maybe%20Maybe"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>BaseM</span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>Maybe</span>   <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-293"></a><a name="instance%20BaseM%20%5b%5d%20%5b%5d"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>BaseM</span> <span class='hs-conid'>[]</span> <span class='hs-conid'>[]</span>         <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-294"></a><a name="instance%20BaseM%20Id%20Id"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>BaseM</span> <span class='hs-conid'>Id</span> <span class='hs-conid'>Id</span>         <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-295"></a><a name="instance%20BaseM%20Lift%20Lift"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>BaseM</span> <span class='hs-conid'>Lift</span> <span class='hs-conid'>Lift</span>     <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-296"></a><a name="instance%20BaseM%20(ST%20s)%20(ST%20s)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ST</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>ST</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-297"></a>
<a name="line-298"></a>
<a name="line-299"></a><a name="instance%20BaseM%20(IdT%20m)%20n"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span>          <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_inBase</span>
<a name="line-300"></a><a name="instance%20BaseM%20(ReaderT%20i%20m)%20n"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span>    <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_inBase</span>
<a name="line-301"></a><a name="instance%20BaseM%20(StateT%20i%20m)%20n"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span>     <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_inBase</span>
<a name="line-302"></a><a name="instance%20BaseM%20(WriterT%20i%20m)%20n"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-303"></a>                     <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span>    <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_inBase</span>
<a name="line-304"></a><a name="instance%20BaseM%20(ExceptionT%20i%20m)%20n"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_inBase</span>
<a name="line-305"></a><a name="instance%20BaseM%20(ChoiceT%20m)%20n"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span>      <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_inBase</span>
<a name="line-306"></a><a name="instance%20BaseM%20(ContT%20i%20m)%20n"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>BaseM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>BaseM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span>      <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>inBase</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_inBase</span>
<a name="line-307"></a>
<a name="line-308"></a>
<a name="line-309"></a><a name="instance%20Monad%20Id"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-conid'>Id</span> <span class='hs-keyword'>where</span>
<a name="line-310"></a>  <span class='hs-varid'>return</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>I</span> <span class='hs-varid'>x</span>
<a name="line-311"></a>  <span class='hs-varid'>fail</span> <span class='hs-varid'>x</span>   <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varid'>x</span>
<a name="line-312"></a>  <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>runId</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-313"></a>
<a name="line-314"></a><a name="instance%20Monad%20Lift"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-conid'>Lift</span> <span class='hs-keyword'>where</span>
<a name="line-315"></a>  <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>L</span> <span class='hs-varid'>x</span>
<a name="line-316"></a>  <span class='hs-varid'>fail</span> <span class='hs-varid'>x</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varid'>x</span>
<a name="line-317"></a>  <span class='hs-conid'>L</span> <span class='hs-varid'>x</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span> <span class='hs-varid'>x</span>     <span class='hs-comment'>-- Note: the pattern is important here</span>
<a name="line-318"></a>                      <span class='hs-comment'>-- because it makes things strict</span>
<a name="line-319"></a>
<a name="line-320"></a>
<a name="line-321"></a><span class='hs-comment'>-- Note: None of the transformers make essential use of the 'fail' method.</span>
<a name="line-322"></a><span class='hs-comment'>-- Instead, they delegate its behavior to the underlying monad.</span>
<a name="line-323"></a>
<a name="line-324"></a><a name="instance%20Monad%20(IdT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-325"></a>  <span class='hs-varid'>return</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_return</span>
<a name="line-326"></a>  <span class='hs-varid'>fail</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_fail</span>
<a name="line-327"></a>  <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-layout'>(</span><span class='hs-varid'>runIdT</span> <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-layout'>(</span><span class='hs-varid'>runIdT</span> <span class='hs-varop'>.</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-328"></a>
<a name="line-329"></a><a name="instance%20Monad%20(ReaderT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-330"></a>  <span class='hs-varid'>return</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_return</span>
<a name="line-331"></a>  <span class='hs-varid'>fail</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_fail</span>
<a name="line-332"></a>  <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runReaderT</span> <span class='hs-varid'>r</span> <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runReaderT</span> <span class='hs-varid'>r</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-333"></a>
<a name="line-334"></a><a name="instance%20Monad%20(StateT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-335"></a>  <span class='hs-varid'>return</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_return</span>
<a name="line-336"></a>  <span class='hs-varid'>fail</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_fail</span>
<a name="line-337"></a>  <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runStateT</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-keyglyph'>\</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runStateT</span> <span class='hs-varid'>s'</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-338"></a>
<a name="line-339"></a><a name="instance%20Monad%20(WriterT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-340"></a>  <span class='hs-varid'>return</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_return</span>
<a name="line-341"></a>  <span class='hs-varid'>fail</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_fail</span>
<a name="line-342"></a>  <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-varop'>$</span> <span class='hs-varid'>unW</span> <span class='hs-varid'>m</span>     <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-keyglyph'>\</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-varid'>w1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-343"></a>                <span class='hs-varid'>unW</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-keyglyph'>\</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>b</span> <span class='hs-varid'>w2</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-344"></a>                <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>b</span> <span class='hs-layout'>(</span><span class='hs-varid'>mappend</span> <span class='hs-varid'>w1</span> <span class='hs-varid'>w2</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-345"></a>
<a name="line-346"></a><a name="instance%20Monad%20(ExceptionT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-347"></a>  <span class='hs-varid'>return</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_return</span>
<a name="line-348"></a>  <span class='hs-varid'>fail</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_fail</span>
<a name="line-349"></a>  <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-varop'>$</span> <span class='hs-varid'>runExceptionT</span> <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>e</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-350"></a>                <span class='hs-keyword'>case</span> <span class='hs-varid'>e</span> <span class='hs-keyword'>of</span>
<a name="line-351"></a>                  <span class='hs-conid'>Left</span> <span class='hs-varid'>x</span>  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-352"></a>                  <span class='hs-conid'>Right</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runExceptionT</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-353"></a>
<a name="line-354"></a><a name="instance%20Monad%20(ChoiceT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-355"></a>  <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Answer</span> <span class='hs-varid'>x</span>
<a name="line-356"></a>  <span class='hs-varid'>fail</span> <span class='hs-varid'>x</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>fail</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-357"></a>
<a name="line-358"></a>  <span class='hs-conid'>Answer</span> <span class='hs-varid'>a</span>  <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span> <span class='hs-varid'>a</span>
<a name="line-359"></a>  <span class='hs-conid'>NoAnswer</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-keyword'>_</span>      <span class='hs-keyglyph'>=</span> <span class='hs-conid'>NoAnswer</span>
<a name="line-360"></a>  <span class='hs-conid'>Choice</span> <span class='hs-varid'>m1</span> <span class='hs-varid'>m2</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Choice</span> <span class='hs-layout'>(</span><span class='hs-varid'>m1</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>m2</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>
<a name="line-361"></a>  <span class='hs-conid'>ChoiceEff</span> <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span>   <span class='hs-keyglyph'>=</span> <span class='hs-conid'>ChoiceEff</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-layout'>(</span><span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-362"></a>
<a name="line-363"></a><a name="instance%20Monad%20(ContT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-364"></a>  <span class='hs-varid'>return</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_return</span>
<a name="line-365"></a>  <span class='hs-varid'>fail</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_fail</span>
<a name="line-366"></a>  <span class='hs-varid'>m</span> <span class='hs-varop'>&gt;&gt;=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>c</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runContT</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runContT</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>m</span>
<a name="line-367"></a>
<a name="line-368"></a><a name="instance%20Functor%20Id"></a><span class='hs-keyword'>instance</span>                       <span class='hs-conid'>Functor</span> <span class='hs-conid'>Id</span>               <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-369"></a><a name="instance%20Functor%20Lift"></a><span class='hs-keyword'>instance</span>                       <span class='hs-conid'>Functor</span> <span class='hs-conid'>Lift</span>             <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-370"></a><a name="instance%20Functor%20(IdT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>          <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span>          <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-371"></a><a name="instance%20Functor%20(ReaderT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>          <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span>    <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-372"></a><a name="instance%20Functor%20(StateT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>          <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span>     <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-373"></a><a name="instance%20Functor%20(WriterT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>    <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-374"></a><a name="instance%20Functor%20(ExceptionT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>          <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-375"></a><a name="instance%20Functor%20(ChoiceT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>          <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span>      <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-376"></a><a name="instance%20Functor%20(ContT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>          <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span>      <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>fmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span>
<a name="line-377"></a>
<a name="line-378"></a><span class='hs-comment'>-- Applicative support ---------------------------------------------------------</span>
<a name="line-379"></a>
<a name="line-380"></a><span class='hs-comment'>-- NOTE: It may be possible to make these more general</span>
<a name="line-381"></a><span class='hs-comment'>-- (i.e., have Applicative, or even Functor transformers)</span>
<a name="line-382"></a>
<a name="line-383"></a><a name="instance%20Applicative%20Id"></a><span class='hs-keyword'>instance</span>              <span class='hs-conid'>Applicative</span> <span class='hs-conid'>Id</span>            <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-384"></a><a name="instance%20Applicative%20Lift"></a><span class='hs-keyword'>instance</span>              <span class='hs-conid'>Applicative</span> <span class='hs-conid'>Lift</span>          <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-385"></a><a name="instance%20Applicative%20(IdT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>       <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-386"></a><a name="instance%20Applicative%20(ReaderT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-387"></a><a name="instance%20Applicative%20(StateT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>  <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-388"></a><a name="instance%20Applicative%20(WriterT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-389"></a>                   <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-390"></a><a name="instance%20Applicative%20(ExceptionT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-391"></a>                                                <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-392"></a><a name="instance%20Applicative%20(ChoiceT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>   <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-393"></a><a name="instance%20Applicative%20(ContT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>   <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;*&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span><span class='hs-layout'>;</span> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-394"></a>
<a name="line-395"></a><a name="instance%20Alternative%20(IdT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-396"></a>           <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>           <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;|&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span><span class='hs-layout'>;</span> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-397"></a><a name="instance%20Alternative%20(ReaderT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-398"></a>           <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>     <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;|&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span><span class='hs-layout'>;</span> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-399"></a><a name="instance%20Alternative%20(StateT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-400"></a>           <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>      <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;|&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span><span class='hs-layout'>;</span> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-401"></a><a name="instance%20Alternative%20(WriterT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-402"></a>           <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>     <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;|&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span><span class='hs-layout'>;</span> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-403"></a><a name="instance%20Alternative%20(ExceptionT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-404"></a>           <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>  <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;|&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span><span class='hs-layout'>;</span> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-405"></a><a name="instance%20Alternative%20(ChoiceT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-406"></a>           <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>       <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;|&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span><span class='hs-layout'>;</span> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-407"></a><a name="instance%20Alternative%20(ContT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-408"></a>           <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>       <span class='hs-keyword'>where</span> <span class='hs-layout'>(</span><span class='hs-varop'>&lt;|&gt;</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span><span class='hs-layout'>;</span> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-409"></a>
<a name="line-410"></a>
<a name="line-411"></a>
<a name="line-412"></a><span class='hs-comment'>-- $Monadic_Value_Recursion</span>
<a name="line-413"></a><span class='hs-comment'>--</span>
<a name="line-414"></a><span class='hs-comment'>-- Recursion that does not duplicate side-effects.</span>
<a name="line-415"></a><span class='hs-comment'>-- For details see Levent Erkok's dissertation.</span>
<a name="line-416"></a><span class='hs-comment'>--</span>
<a name="line-417"></a><span class='hs-comment'>-- Monadic types built with 'ContT' and 'ChoiceT' do not support</span>
<a name="line-418"></a><span class='hs-comment'>-- monadic value recursion.</span>
<a name="line-419"></a>
<a name="line-420"></a><a name="instance%20MonadFix%20Id"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadFix</span> <span class='hs-conid'>Id</span> <span class='hs-keyword'>where</span>
<a name="line-421"></a>  <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span>  <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>runId</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>in</span> <span class='hs-varid'>m</span>
<a name="line-422"></a>
<a name="line-423"></a><a name="instance%20MonadFix%20Lift"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadFix</span> <span class='hs-conid'>Lift</span> <span class='hs-keyword'>where</span>
<a name="line-424"></a>  <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span>  <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>runLift</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>in</span> <span class='hs-varid'>m</span>
<a name="line-425"></a>
<a name="line-426"></a><a name="instance%20MonadFix%20(IdT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadFix</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadFix</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-427"></a>  <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-layout'>(</span><span class='hs-varid'>mfix</span> <span class='hs-layout'>(</span><span class='hs-varid'>runIdT</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-428"></a>
<a name="line-429"></a><a name="instance%20MonadFix%20(ReaderT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadFix</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadFix</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-430"></a>  <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>mfix</span> <span class='hs-layout'>(</span><span class='hs-varid'>runReaderT</span> <span class='hs-varid'>r</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-431"></a>
<a name="line-432"></a><a name="instance%20MonadFix%20(StateT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadFix</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadFix</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-433"></a>  <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>mfix</span> <span class='hs-layout'>(</span><span class='hs-varid'>runStateT</span> <span class='hs-varid'>s</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fst</span><span class='hs-layout'>)</span>
<a name="line-434"></a>
<a name="line-435"></a><a name="instance%20MonadFix%20(WriterT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadFix</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadFix</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-436"></a>  <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-varop'>$</span> <span class='hs-varid'>mfix</span> <span class='hs-layout'>(</span><span class='hs-varid'>unW</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span> <span class='hs-varop'>.</span> <span class='hs-varid'>val</span><span class='hs-layout'>)</span>
<a name="line-437"></a>    <span class='hs-keyword'>where</span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span>
<a name="line-438"></a>
<a name="line-439"></a><span class='hs-comment'>-- No instance for ChoiceT</span>
<a name="line-440"></a>
<a name="line-441"></a><a name="instance%20MonadFix%20(ExceptionT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadFix</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadFix</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-442"></a>  <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-varop'>$</span> <span class='hs-varid'>mfix</span> <span class='hs-layout'>(</span><span class='hs-varid'>runExceptionT</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fromRight</span><span class='hs-layout'>)</span>
<a name="line-443"></a>    <span class='hs-keyword'>where</span> <span class='hs-varid'>fromRight</span> <span class='hs-layout'>(</span><span class='hs-conid'>Right</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span>
<a name="line-444"></a>          <span class='hs-varid'>fromRight</span> <span class='hs-keyword'>_</span>         <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"ExceptionT: mfix looped."</span>
<a name="line-445"></a>
<a name="line-446"></a><span class='hs-comment'>-- No instance for ContT</span>
<a name="line-447"></a>
<a name="line-448"></a><a name="instance%20MonadPlus%20(IdT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-449"></a>  <span class='hs-varid'>mzero</span>               <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_mzero</span>
<a name="line-450"></a>  <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-conid'>IT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>IT</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-layout'>(</span><span class='hs-varid'>mplus</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-451"></a>
<a name="line-452"></a><a name="instance%20MonadPlus%20(ReaderT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-453"></a>  <span class='hs-varid'>mzero</span>             <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_mzero</span>
<a name="line-454"></a>  <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-conid'>R</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>R</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-455"></a>
<a name="line-456"></a><a name="instance%20MonadPlus%20(StateT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-457"></a>  <span class='hs-varid'>mzero</span>             <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_mzero</span>
<a name="line-458"></a>  <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-459"></a>
<a name="line-460"></a><a name="instance%20MonadPlus%20(WriterT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-461"></a>  <span class='hs-varid'>mzero</span>               <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_mzero</span>
<a name="line-462"></a>  <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-conid'>W</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>W</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-layout'>(</span><span class='hs-varid'>mplus</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-463"></a>
<a name="line-464"></a><a name="instance%20MonadPlus%20(ExceptionT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-465"></a>  <span class='hs-varid'>mzero</span>             <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_mzero</span>
<a name="line-466"></a>  <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-conid'>X</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>X</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-layout'>(</span><span class='hs-varid'>mplus</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-467"></a>
<a name="line-468"></a><a name="instance%20MonadPlus%20(ChoiceT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-469"></a>  <span class='hs-varid'>mzero</span>             <span class='hs-keyglyph'>=</span> <span class='hs-conid'>NoAnswer</span>
<a name="line-470"></a>  <span class='hs-varid'>mplus</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span>         <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Choice</span> <span class='hs-varid'>m</span> <span class='hs-varid'>n</span>
<a name="line-471"></a>
<a name="line-472"></a><a name="instance%20MonadPlus%20(ContT%20i%20m)"></a><span class='hs-comment'>-- Alternatives share the continuation.</span>
<a name="line-473"></a><a name="instance%20MonadPlus%20(ContT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-474"></a>  <span class='hs-varid'>mzero</span>             <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_mzero</span>
<a name="line-475"></a>  <span class='hs-varid'>mplus</span> <span class='hs-layout'>(</span><span class='hs-conid'>C</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>C</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>k</span> <span class='hs-varop'>`mplus`</span> <span class='hs-varid'>n</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>
<a name="line-476"></a>
<a name="line-477"></a>
<a name="line-478"></a><span class='hs-comment'>-- $Effects</span>
<a name="line-479"></a><span class='hs-comment'>--</span>
<a name="line-480"></a><span class='hs-comment'>-- The following classes define overloaded operations</span>
<a name="line-481"></a><span class='hs-comment'>-- that can be used to define effectful computations.</span>
<a name="line-482"></a>
<a name="line-483"></a>
<a name="line-484"></a><a name="ReaderM"></a><span class='hs-comment'>-- | Classifies monads that provide access to a context of type @i@.</span>
<a name="line-485"></a><a name="ReaderM"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-486"></a>  <span class='hs-comment'>-- | Get the context.</span>
<a name="line-487"></a>  <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-488"></a>
<a name="line-489"></a><a name="instance%20ReaderM%20(ReaderT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-490"></a>  <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-varid'>return</span>
<a name="line-491"></a>
<a name="line-492"></a><a name="instance%20ReaderM%20(IdT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span>           <span class='hs-keyword'>where</span> <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_ask</span>
<a name="line-493"></a><a name="instance%20ReaderM%20(WriterT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-494"></a>                       <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span>     <span class='hs-keyword'>where</span> <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_ask</span>
<a name="line-495"></a><a name="instance%20ReaderM%20(StateT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span>      <span class='hs-keyword'>where</span> <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_ask</span>
<a name="line-496"></a><a name="instance%20ReaderM%20(ExceptionT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span>  <span class='hs-keyword'>where</span> <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_ask</span>
<a name="line-497"></a><a name="instance%20ReaderM%20(ChoiceT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span>       <span class='hs-keyword'>where</span> <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_ask</span>
<a name="line-498"></a><a name="instance%20ReaderM%20(ContT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span>       <span class='hs-keyword'>where</span> <span class='hs-varid'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_ask</span>
<a name="line-499"></a>
<a name="line-500"></a>
<a name="line-501"></a><a name="WriterM"></a><span class='hs-comment'>-- | Classifies monads that can collect values of type @i@.</span>
<a name="line-502"></a><a name="WriterM"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-503"></a>  <span class='hs-comment'>-- | Add a value to the collection.</span>
<a name="line-504"></a>  <span class='hs-varid'>put</span>  <span class='hs-keyglyph'>::</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-505"></a>
<a name="line-506"></a><a name="instance%20WriterM%20(WriterT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-507"></a>  <span class='hs-varid'>put</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-conid'>()</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-508"></a>
<a name="line-509"></a><a name="instance%20WriterM%20(IdT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span>          <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>put</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_put</span>
<a name="line-510"></a><a name="instance%20WriterM%20(ReaderT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span>    <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>put</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_put</span>
<a name="line-511"></a><a name="instance%20WriterM%20(StateT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span>     <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>put</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_put</span>
<a name="line-512"></a><a name="instance%20WriterM%20(ExceptionT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>put</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_put</span>
<a name="line-513"></a><a name="instance%20WriterM%20(ChoiceT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span>      <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>put</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_put</span>
<a name="line-514"></a><a name="instance%20WriterM%20(ContT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>WriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span>      <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>put</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_put</span>
<a name="line-515"></a>
<a name="line-516"></a><a name="StateM"></a><span class='hs-comment'>-- | Classifies monads that propagate a state component of type @i@.</span>
<a name="line-517"></a><a name="StateM"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-518"></a>  <span class='hs-comment'>-- | Get the state.</span>
<a name="line-519"></a>  <span class='hs-varid'>get</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span>
<a name="line-520"></a>  <span class='hs-comment'>-- | Set the state.</span>
<a name="line-521"></a>  <span class='hs-varid'>set</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-522"></a>
<a name="line-523"></a><a name="instance%20StateM%20(StateT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-524"></a>  <span class='hs-varid'>get</span>   <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-525"></a>  <span class='hs-varid'>set</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>()</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-526"></a>
<a name="line-527"></a><a name="instance%20StateM%20(IdT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-528"></a>  <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_get</span><span class='hs-layout'>;</span> <span class='hs-varid'>set</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_set</span>
<a name="line-529"></a><a name="instance%20StateM%20(ReaderT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-530"></a>  <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_get</span><span class='hs-layout'>;</span> <span class='hs-varid'>set</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_set</span>
<a name="line-531"></a><a name="instance%20StateM%20(WriterT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-532"></a>  <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_get</span><span class='hs-layout'>;</span> <span class='hs-varid'>set</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_set</span>
<a name="line-533"></a><a name="instance%20StateM%20(ExceptionT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-534"></a>  <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_get</span><span class='hs-layout'>;</span> <span class='hs-varid'>set</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_set</span>
<a name="line-535"></a><a name="instance%20StateM%20(ChoiceT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-536"></a>  <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_get</span><span class='hs-layout'>;</span> <span class='hs-varid'>set</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_set</span>
<a name="line-537"></a><a name="instance%20StateM%20(ContT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>StateM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-538"></a>  <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_get</span><span class='hs-layout'>;</span> <span class='hs-varid'>set</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_set</span>
<a name="line-539"></a>
<a name="line-540"></a><a name="ExceptionM"></a><span class='hs-comment'>-- | Classifies monads that support raising exceptions of type @i@.</span>
<a name="line-541"></a><a name="ExceptionM"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-542"></a>  <span class='hs-comment'>-- | Raise an exception.</span>
<a name="line-543"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-544"></a>
<a name="line-545"></a><span class='hs-cpp'>#ifdef USE_BASE3</span>
<a name="line-546"></a><a name="instance%20ExceptionM%20IO%20IO.Exception"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Exception</span> <span class='hs-keyword'>where</span>
<a name="line-547"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-varid'>throwIO</span>
<a name="line-548"></a><span class='hs-cpp'>#else</span>
<a name="line-549"></a><a name="instance%20ExceptionM%20IO%20IO.SomeException"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>SomeException</span> <span class='hs-keyword'>where</span>
<a name="line-550"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-varid'>throwIO</span>
<a name="line-551"></a><span class='hs-cpp'>#endif</span>
<a name="line-552"></a>
<a name="line-553"></a><a name="instance%20ExceptionM%20(ExceptionT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-554"></a>  <span class='hs-varid'>raise</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-555"></a>
<a name="line-556"></a><a name="instance%20ExceptionM%20(IdT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-557"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_raise</span>
<a name="line-558"></a><a name="instance%20ExceptionM%20(ReaderT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-559"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_raise</span>
<a name="line-560"></a><a name="instance%20ExceptionM%20(WriterT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-561"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_raise</span>
<a name="line-562"></a><a name="instance%20ExceptionM%20(StateT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span>  <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-563"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_raise</span>
<a name="line-564"></a><a name="instance%20ExceptionM%20(ChoiceT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span>   <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-565"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_raise</span>
<a name="line-566"></a><a name="instance%20ExceptionM%20(ContT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span>   <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-567"></a>  <span class='hs-varid'>raise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_raise</span>
<a name="line-568"></a>
<a name="line-569"></a>
<a name="line-570"></a><span class='hs-comment'>-- The following instances differ from the others because the</span>
<a name="line-571"></a><span class='hs-comment'>-- liftings are not as uniform (although they certainly follow a pattern).</span>
<a name="line-572"></a>
<a name="line-573"></a><a name="ContM"></a><span class='hs-comment'>-- | Classifies monads that provide access to a computation's continuation.</span>
<a name="line-574"></a><a name="ContM"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span> <span class='hs-keyword'>where</span>
<a name="line-575"></a>  <span class='hs-comment'>-- | Capture the current continuation.</span>
<a name="line-576"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Label</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-577"></a>
<a name="line-578"></a>
<a name="line-579"></a><a name="liftJump"></a><span class='hs-comment'>-- This captures a common pattern in the lifted definitions of `callWithCC`.</span>
<a name="line-580"></a><span class='hs-definition'>liftJump</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span> <span class='hs-conid'>MonadT</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span>
<a name="line-581"></a>  <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-582"></a>  <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Label</span> <span class='hs-layout'>(</span><span class='hs-varid'>t</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-583"></a>  <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>b</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Label</span>    <span class='hs-varid'>m</span> <span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>t</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-584"></a><span class='hs-definition'>liftJump</span> <span class='hs-varid'>ans</span> <span class='hs-varid'>f</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Lab</span> <span class='hs-layout'>(</span><span class='hs-varid'>lift</span> <span class='hs-varop'>$</span> <span class='hs-varid'>jump</span> <span class='hs-varop'>$</span> <span class='hs-varid'>l</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ans</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-585"></a>
<a name="line-586"></a>
<a name="line-587"></a><a name="instance%20ContM%20(IdT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-588"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-varop'>$</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runIdT</span> <span class='hs-varop'>$</span> <span class='hs-varid'>liftJump</span> <span class='hs-varid'>id</span> <span class='hs-varid'>f</span> <span class='hs-varid'>k</span>
<a name="line-589"></a>
<a name="line-590"></a><a name="instance%20ContM%20(ReaderT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-591"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runReaderT</span> <span class='hs-varid'>r</span> <span class='hs-varop'>$</span> <span class='hs-varid'>liftJump</span> <span class='hs-varid'>id</span> <span class='hs-varid'>f</span> <span class='hs-varid'>k</span>
<a name="line-592"></a>
<a name="line-593"></a><a name="instance%20ContM%20(StateT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-594"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runStateT</span> <span class='hs-varid'>s</span> <span class='hs-varop'>$</span> <span class='hs-varid'>liftJump</span> <span class='hs-layout'>(</span><span class='hs-varid'>ans</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-varid'>k</span>
<a name="line-595"></a>    <span class='hs-keyword'>where</span> <span class='hs-varid'>ans</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-596"></a>
<a name="line-597"></a><a name="instance%20ContM%20(WriterT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-598"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-varop'>$</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>unW</span> <span class='hs-varop'>$</span> <span class='hs-varid'>liftJump</span> <span class='hs-layout'>(</span><span class='hs-varop'>`P`</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-varid'>k</span>
<a name="line-599"></a>
<a name="line-600"></a><a name="instance%20ContM%20(ExceptionT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-601"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-varop'>$</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runExceptionT</span> <span class='hs-varop'>$</span> <span class='hs-varid'>liftJump</span> <span class='hs-conid'>Right</span> <span class='hs-varid'>f</span> <span class='hs-varid'>k</span>
<a name="line-602"></a>
<a name="line-603"></a><a name="instance%20ContM%20(ChoiceT%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-604"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>ChoiceEff</span> <span class='hs-varop'>$</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>liftJump</span> <span class='hs-conid'>Answer</span> <span class='hs-varid'>f</span> <span class='hs-varid'>k</span>
<a name="line-605"></a>    <span class='hs-comment'>-- ??? What does this do ???</span>
<a name="line-606"></a>
<a name="line-607"></a><a name="instance%20ContM%20(ContT%20i%20m)"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>ContM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-608"></a>  <span class='hs-varid'>callWithCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>runContT</span> <span class='hs-varid'>k</span> <span class='hs-varop'>$</span> <span class='hs-varid'>f</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Lab</span> <span class='hs-layout'>(</span><span class='hs-conid'>C</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>k</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-609"></a>
<a name="line-610"></a><span class='hs-comment'>-- $Nested_Exec</span>
<a name="line-611"></a><span class='hs-comment'>--</span>
<a name="line-612"></a><span class='hs-comment'>-- The following classes define operations that are overloaded</span>
<a name="line-613"></a><span class='hs-comment'>-- versions of the @run@ operations.   Unlike the @run@ operations,</span>
<a name="line-614"></a><span class='hs-comment'>-- these functions do not change the type of the computation (i.e., they</span>
<a name="line-615"></a><span class='hs-comment'>-- do not remove a layer).  Instead, they perform the effects in</span>
<a name="line-616"></a><span class='hs-comment'>-- a ``separate effect thread''.</span>
<a name="line-617"></a>
<a name="line-618"></a><a name="RunReaderM"></a><span class='hs-comment'>-- | Classifies monads that support changing the context for a</span>
<a name="line-619"></a><a name="RunReaderM"></a><span class='hs-comment'>-- sub-computation.</span>
<a name="line-620"></a><a name="RunReaderM"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-621"></a>  <span class='hs-comment'>-- | Change the context for the duration of a sub-computation.</span>
<a name="line-622"></a>  <span class='hs-varid'>local</span>        <span class='hs-keyglyph'>::</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-623"></a>  <span class='hs-comment'>-- prop(?): local i (m1 &gt;&gt; m2) = local i m1 &gt;&gt; local i m2</span>
<a name="line-624"></a>
<a name="line-625"></a><a name="instance%20RunReaderM%20(ReaderT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>        <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span>    <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-626"></a>  <span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>runReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-627"></a>
<a name="line-628"></a><a name="instance%20RunReaderM%20(IdT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-629"></a>  <span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>IT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-layout'>(</span><span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-630"></a><a name="instance%20RunReaderM%20(WriterT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-631"></a>  <span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>W</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-layout'>(</span><span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-632"></a><a name="instance%20RunReaderM%20(StateT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span>     <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-633"></a>  <span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-varop'>.</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-634"></a><a name="instance%20RunReaderM%20(ExceptionT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-635"></a>  <span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>X</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-layout'>(</span><span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-636"></a>
<a name="line-637"></a><a name="instance%20RunReaderM%20(ContT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-638"></a>  <span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>C</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-layout'>(</span><span class='hs-varid'>local</span> <span class='hs-varid'>i</span> <span class='hs-varop'>.</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-639"></a>
<a name="line-640"></a><a name="RunWriterM"></a><span class='hs-comment'>-- | Classifies monads that support collecting the output of</span>
<a name="line-641"></a><a name="RunWriterM"></a><span class='hs-comment'>-- a sub-computation.</span>
<a name="line-642"></a><a name="RunWriterM"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-643"></a>  <span class='hs-comment'>-- | Collect the output from a sub-computation.</span>
<a name="line-644"></a>  <span class='hs-varid'>collect</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-645"></a>
<a name="line-646"></a><a name="instance%20RunWriterM%20(WriterT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-647"></a>  <span class='hs-varid'>collect</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>runWriterT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-648"></a>
<a name="line-649"></a><a name="instance%20RunWriterM%20(IdT%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunWriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-650"></a>  <span class='hs-varid'>collect</span> <span class='hs-layout'>(</span><span class='hs-conid'>IT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-layout'>(</span><span class='hs-varid'>collect</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-651"></a><a name="instance%20RunWriterM%20(ReaderT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunWriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-652"></a>  <span class='hs-varid'>collect</span> <span class='hs-layout'>(</span><span class='hs-conid'>R</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-layout'>(</span><span class='hs-varid'>collect</span> <span class='hs-varop'>.</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-653"></a><a name="instance%20RunWriterM%20(StateT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunWriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-654"></a>  <span class='hs-varid'>collect</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-varid'>swap</span> <span class='hs-varop'>.</span> <span class='hs-varid'>collect</span> <span class='hs-varop'>.</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-655"></a>    <span class='hs-keyword'>where</span> <span class='hs-varid'>swap</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-656"></a><a name="instance%20RunWriterM%20(ExceptionT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunWriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-657"></a>  <span class='hs-varid'>collect</span> <span class='hs-layout'>(</span><span class='hs-conid'>X</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>X</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-varid'>swap</span> <span class='hs-layout'>(</span><span class='hs-varid'>collect</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-658"></a>    <span class='hs-keyword'>where</span> <span class='hs-varid'>swap</span> <span class='hs-layout'>(</span><span class='hs-conid'>Right</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Right</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-659"></a>          <span class='hs-varid'>swap</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-keyword'>_</span><span class='hs-layout'>)</span>   <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Left</span> <span class='hs-varid'>x</span>
<a name="line-660"></a><a name="instance%20RunWriterM%20(ContT%20i%20m)%20j"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunWriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>j</span><span class='hs-layout'>,</span> <span class='hs-conid'>MonadFix</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>j</span> <span class='hs-keyword'>where</span>
<a name="line-661"></a>  <span class='hs-varid'>collect</span> <span class='hs-layout'>(</span><span class='hs-conid'>C</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>fst</span> <span class='hs-varop'>`liftM`</span>
<a name="line-662"></a>                                <span class='hs-varid'>mfix</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>collect</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-663"></a>
<a name="line-664"></a>
<a name="line-665"></a><span class='hs-comment'>-- $WriterM_ExceptionT</span>
<a name="line-666"></a><span class='hs-comment'>--</span>
<a name="line-667"></a><span class='hs-comment'>-- About the 'WriterM' instance:</span>
<a name="line-668"></a><span class='hs-comment'>-- If an exception is risen while we are collecting output,</span>
<a name="line-669"></a><span class='hs-comment'>-- then the output is lost.  If the output is important,</span>
<a name="line-670"></a><span class='hs-comment'>-- then use 'try' to ensure that no exception may occur.</span>
<a name="line-671"></a><span class='hs-comment'>-- Example:</span>
<a name="line-672"></a><span class='hs-comment'>--</span>
<a name="line-673"></a><span class='hs-comment'>-- &gt; do (r,w) &lt;- collect (try m)</span>
<a name="line-674"></a><span class='hs-comment'>-- &gt;    case r of</span>
<a name="line-675"></a><span class='hs-comment'>-- &gt;      Left err -&gt; ...do something...</span>
<a name="line-676"></a><span class='hs-comment'>-- &gt;      Right a  -&gt; ...do something...</span>
<a name="line-677"></a>
<a name="line-678"></a><a name="RunExceptionM"></a><span class='hs-comment'>-- | Classifies monads that support handling of exceptions.</span>
<a name="line-679"></a><a name="RunExceptionM"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-680"></a>  <span class='hs-comment'>-- | Convert computations that may raise an exception</span>
<a name="line-681"></a>  <span class='hs-comment'>-- into computations that do not raise exception but instead,</span>
<a name="line-682"></a>  <span class='hs-comment'>-- yield a tagged results.  Exceptions are tagged with "Left",</span>
<a name="line-683"></a>  <span class='hs-comment'>-- successful computations are tagged with "Right".</span>
<a name="line-684"></a>  <span class='hs-varid'>try</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-varid'>i</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-685"></a>
<a name="line-686"></a><span class='hs-cpp'>#ifdef USE_BASE3</span>
<a name="line-687"></a><a name="instance%20RunExceptionM%20IO%20IO.Exception"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Exception</span> <span class='hs-keyword'>where</span>
<a name="line-688"></a>  <span class='hs-varid'>try</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-varid'>try</span>
<a name="line-689"></a><span class='hs-cpp'>#else</span>
<a name="line-690"></a><a name="instance%20RunExceptionM%20IO%20IO.SomeException"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>SomeException</span> <span class='hs-keyword'>where</span>
<a name="line-691"></a>  <span class='hs-varid'>try</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-varid'>try</span>
<a name="line-692"></a><span class='hs-cpp'>#endif</span>
<a name="line-693"></a>
<a name="line-694"></a><a name="instance%20RunExceptionM%20(ExceptionT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-695"></a>  <span class='hs-varid'>try</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>runExceptionT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-696"></a>
<a name="line-697"></a><a name="instance%20RunExceptionM%20(IdT%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-698"></a>  <span class='hs-varid'>try</span> <span class='hs-layout'>(</span><span class='hs-conid'>IT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IT</span> <span class='hs-layout'>(</span><span class='hs-varid'>try</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-699"></a><a name="instance%20RunExceptionM%20(ReaderT%20j%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>j</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-700"></a>  <span class='hs-varid'>try</span> <span class='hs-layout'>(</span><span class='hs-conid'>R</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>R</span> <span class='hs-layout'>(</span><span class='hs-varid'>try</span> <span class='hs-varop'>.</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-701"></a><a name="instance%20RunExceptionM%20(WriterT%20j%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>j</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-702"></a>  <span class='hs-varid'>try</span> <span class='hs-layout'>(</span><span class='hs-conid'>W</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>W</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-varid'>swap</span> <span class='hs-layout'>(</span><span class='hs-varid'>try</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-703"></a>    <span class='hs-keyword'>where</span> <span class='hs-varid'>swap</span> <span class='hs-layout'>(</span><span class='hs-conid'>Right</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>a</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-conid'>Right</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varid'>w</span>
<a name="line-704"></a>          <span class='hs-varid'>swap</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span>         <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span> <span class='hs-varid'>mempty</span>
<a name="line-705"></a><a name="instance%20RunExceptionM%20(StateT%20j%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>RunExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>j</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-706"></a>  <span class='hs-varid'>try</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>liftM</span> <span class='hs-layout'>(</span><span class='hs-varid'>swap</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>try</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-707"></a>    <span class='hs-keyword'>where</span> <span class='hs-varid'>swap</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>Right</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>Right</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-708"></a>          <span class='hs-varid'>swap</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span>       <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>e</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-709"></a>
<a name="line-710"></a><a name="AbortM"></a><span class='hs-comment'>-- | Classifies monads that support aborting the program and returning</span>
<a name="line-711"></a><a name="AbortM"></a><span class='hs-comment'>-- a given final result of type 'i'.</span>
<a name="line-712"></a><a name="AbortM"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-713"></a>
<a name="line-714"></a>  <span class='hs-comment'>-- | Abort the program with the given value as final result.</span>
<a name="line-715"></a>  <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-716"></a>
<a name="line-717"></a><a name="instance%20AbortM%20(ContT%20i%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContT</span> <span class='hs-varid'>i</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-718"></a>  <span class='hs-varid'>abort</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>C</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span>
<a name="line-719"></a>
<a name="line-720"></a><a name="instance%20AbortM%20IO%20ExitCode"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>AbortM</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>ExitCode</span> <span class='hs-keyword'>where</span>
<a name="line-721"></a>  <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>exitWith</span>
<a name="line-722"></a>
<a name="line-723"></a><a name="instance%20AbortM%20(IdT%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-layout'>(</span><span class='hs-conid'>IdT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span>           <span class='hs-keyword'>where</span> <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_abort</span>
<a name="line-724"></a><a name="instance%20AbortM%20(ReaderT%20j%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ReaderT</span> <span class='hs-varid'>j</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span>     <span class='hs-keyword'>where</span> <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_abort</span>
<a name="line-725"></a><a name="instance%20AbortM%20(WriterT%20j%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span><span class='hs-layout'>,</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>j</span><span class='hs-layout'>)</span>
<a name="line-726"></a>                    <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-layout'>(</span><span class='hs-conid'>WriterT</span> <span class='hs-varid'>j</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span>     <span class='hs-keyword'>where</span> <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_abort</span>
<a name="line-727"></a><a name="instance%20AbortM%20(StateT%20j%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-layout'>(</span><span class='hs-conid'>StateT</span> <span class='hs-varid'>j</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span>      <span class='hs-keyword'>where</span> <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_abort</span>
<a name="line-728"></a><a name="instance%20AbortM%20(ExceptionT%20j%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ExceptionT</span> <span class='hs-varid'>j</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span>  <span class='hs-keyword'>where</span> <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_abort</span>
<a name="line-729"></a><a name="instance%20AbortM%20(ChoiceT%20m)%20i"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>AbortM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>AbortM</span> <span class='hs-layout'>(</span><span class='hs-conid'>ChoiceT</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>i</span>       <span class='hs-keyword'>where</span> <span class='hs-varid'>abort</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_abort</span>
<a name="line-730"></a>
<a name="line-731"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-732"></a><span class='hs-comment'>-- Some convenient functions for working with continuations.</span>
<a name="line-733"></a>
<a name="line-734"></a><a name="Label"></a><span class='hs-comment'>-- | An explicit representation for monadic continuations.</span>
<a name="line-735"></a><a name="Label"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>Label</span> <span class='hs-varid'>m</span>     <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Lab</span> <span class='hs-layout'>(</span><span class='hs-keyword'>forall</span> <span class='hs-varid'>b</span><span class='hs-varop'>.</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-736"></a>
<a name="line-737"></a><a name="labelCC"></a><span class='hs-comment'>-- | Capture the current continuation.</span>
<a name="line-738"></a><span class='hs-comment'>-- This function is like 'return', except that it also captures</span>
<a name="line-739"></a><span class='hs-comment'>-- the current continuation.  Later, we can use 'jump' to repeat the</span>
<a name="line-740"></a><span class='hs-comment'>-- computation from this point onwards but with a possibly different value.</span>
<a name="line-741"></a><span class='hs-definition'>labelCC</span>            <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Label</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-742"></a><span class='hs-definition'>labelCC</span> <span class='hs-varid'>x</span>           <span class='hs-keyglyph'>=</span> <span class='hs-varid'>callWithCC</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>l</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>label</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Lab</span> <span class='hs-layout'>(</span><span class='hs-varid'>jump</span> <span class='hs-layout'>(</span><span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>label</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-743"></a>                                        <span class='hs-keyword'>in</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>label</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-744"></a>
<a name="line-745"></a><a name="labelCC_"></a><span class='hs-comment'>-- | Capture the current continuation.</span>
<a name="line-746"></a><span class='hs-comment'>-- Later we can use `jump` to restart the program from this point.</span>
<a name="line-747"></a><span class='hs-definition'>labelCC_</span>           <span class='hs-keyglyph'>::</span> <span class='hs-keyword'>forall</span> <span class='hs-varid'>m</span><span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Label</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-748"></a><span class='hs-definition'>labelCC_</span>            <span class='hs-keyglyph'>=</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>   <span class='hs-comment'>-- Signature matters!!!</span>
<a name="line-749"></a>                                             <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>jump</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Lab</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-750"></a>                                         <span class='hs-keyword'>in</span> <span class='hs-varid'>x</span>
<a name="line-751"></a>
<a name="line-752"></a><a name="callCC"></a><span class='hs-comment'>-- | A version of `callWithCC` that avoids the need for an explicit</span>
<a name="line-753"></a><span class='hs-comment'>-- use of the `jump` function.</span>
<a name="line-754"></a><span class='hs-definition'>callCC</span>             <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ContM</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-755"></a><span class='hs-definition'>callCC</span> <span class='hs-varid'>f</span>            <span class='hs-keyglyph'>=</span> <span class='hs-varid'>callWithCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>l</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>f</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>jump</span> <span class='hs-varop'>$</span> <span class='hs-varid'>l</span> <span class='hs-varid'>a</span>
<a name="line-756"></a>
<a name="line-757"></a><a name="labelC"></a><span class='hs-comment'>-- | Label a given continuation.</span>
<a name="line-758"></a><span class='hs-definition'>labelC</span>             <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-keyword'>forall</span> <span class='hs-varid'>b</span><span class='hs-varop'>.</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Label</span> <span class='hs-varid'>m</span>
<a name="line-759"></a><span class='hs-definition'>labelC</span> <span class='hs-varid'>k</span>            <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Lab</span> <span class='hs-varid'>k</span>
<a name="line-760"></a>
<a name="line-761"></a><a name="jump"></a><span class='hs-comment'>-- | Restart a previously captured computation.</span>
<a name="line-762"></a><span class='hs-definition'>jump</span>               <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Label</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-763"></a><span class='hs-definition'>jump</span> <span class='hs-layout'>(</span><span class='hs-conid'>Lab</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>       <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span>
<a name="line-764"></a>
<a name="line-765"></a>
<a name="line-766"></a>
<a name="line-767"></a>
<a name="line-768"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-769"></a>
<a name="line-770"></a><a name="asks"></a><span class='hs-comment'>-- | Apply a function to the environment.</span>
<a name="line-771"></a><span class='hs-comment'>-- Useful for accessing environmnt components.</span>
<a name="line-772"></a><span class='hs-definition'>asks</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-773"></a><span class='hs-definition'>asks</span> <span class='hs-varid'>f</span>      <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>ask</span>
<a name="line-774"></a>                 <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-775"></a>
<a name="line-776"></a><a name="puts"></a><span class='hs-comment'>-- | Add content the output and return a result.</span>
<a name="line-777"></a><span class='hs-definition'>puts</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>WriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-778"></a><span class='hs-definition'>puts</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>put</span> <span class='hs-varid'>w</span> <span class='hs-varop'>&gt;&gt;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>a</span>
<a name="line-779"></a>
<a name="line-780"></a><a name="sets"></a><span class='hs-comment'>-- | Update the state and return a result.</span>
<a name="line-781"></a><span class='hs-definition'>sets</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-782"></a><span class='hs-definition'>sets</span> <span class='hs-varid'>f</span>      <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>get</span>
<a name="line-783"></a>                 <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span>
<a name="line-784"></a>                 <span class='hs-varid'>set</span> <span class='hs-varid'>s1</span>
<a name="line-785"></a>                 <span class='hs-varid'>return</span> <span class='hs-varid'>a</span>
<a name="line-786"></a>
<a name="line-787"></a><a name="sets_"></a><span class='hs-comment'>-- | Updates the state with the given function.</span>
<a name="line-788"></a><span class='hs-definition'>sets_</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>StateM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-789"></a><span class='hs-definition'>sets_</span> <span class='hs-varid'>f</span>     <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>get</span>
<a name="line-790"></a>                 <span class='hs-varid'>set</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-791"></a><a name="raises"></a><span class='hs-comment'>-- | Either raise an exception or return a value.</span>
<a name="line-792"></a><span class='hs-comment'>-- 'Left' values signify the we should raise an exception,</span>
<a name="line-793"></a><span class='hs-comment'>-- 'Right' values indicate success.</span>
<a name="line-794"></a><span class='hs-definition'>raises</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-conid'>Either</span> <span class='hs-varid'>x</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-795"></a><span class='hs-definition'>raises</span> <span class='hs-layout'>(</span><span class='hs-conid'>Right</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>a</span>
<a name="line-796"></a><span class='hs-definition'>raises</span> <span class='hs-layout'>(</span><span class='hs-conid'>Left</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>   <span class='hs-keyglyph'>=</span> <span class='hs-varid'>raise</span> <span class='hs-varid'>x</span>
<a name="line-797"></a>
<a name="line-798"></a><span class='hs-comment'>-- for ChoiceT we already have "msum"</span>
<a name="line-799"></a><span class='hs-comment'>-- for ContT, not sure if it makes sense.</span>
<a name="line-800"></a>
<a name="line-801"></a><a name="mapReader"></a><span class='hs-comment'>-- | Modify the environment for the duration of a computation.</span>
<a name="line-802"></a><span class='hs-definition'>mapReader</span>        <span class='hs-keyglyph'>::</span> <span class='hs-conid'>RunReaderM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-803"></a><span class='hs-definition'>mapReader</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span>     <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>ask</span>
<a name="line-804"></a>                       <span class='hs-varid'>local</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-varid'>m</span>
<a name="line-805"></a>
<a name="line-806"></a><a name="mapWriter"></a><span class='hs-comment'>-- | Modify the output of a computation.</span>
<a name="line-807"></a><span class='hs-definition'>mapWriter</span>        <span class='hs-keyglyph'>::</span> <span class='hs-conid'>RunWriterM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>w</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-808"></a><span class='hs-definition'>mapWriter</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span>     <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>collect</span> <span class='hs-varid'>m</span>
<a name="line-809"></a>                       <span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-810"></a>                       <span class='hs-varid'>return</span> <span class='hs-varid'>a</span>
<a name="line-811"></a>
<a name="line-812"></a><a name="mapException"></a><span class='hs-comment'>-- | Modify the exception that was risen by a computation.</span>
<a name="line-813"></a><span class='hs-definition'>mapException</span>     <span class='hs-keyglyph'>::</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-814"></a><span class='hs-definition'>mapException</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span>  <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>try</span> <span class='hs-varid'>m</span>
<a name="line-815"></a>                       <span class='hs-keyword'>case</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>of</span>
<a name="line-816"></a>                         <span class='hs-conid'>Right</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>a</span>
<a name="line-817"></a>                         <span class='hs-conid'>Left</span> <span class='hs-varid'>x</span>  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>raise</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-818"></a>
<a name="line-819"></a><a name="handle"></a><span class='hs-comment'>-- | Apply the given exception handler, if a computation raises an exception.</span>
<a name="line-820"></a><span class='hs-definition'>handle</span>           <span class='hs-keyglyph'>::</span> <span class='hs-conid'>RunExceptionM</span> <span class='hs-varid'>m</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-821"></a><span class='hs-definition'>handle</span> <span class='hs-varid'>m</span> <span class='hs-varid'>f</span>        <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>try</span> <span class='hs-varid'>m</span>
<a name="line-822"></a>                       <span class='hs-keyword'>case</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>of</span>
<a name="line-823"></a>                         <span class='hs-conid'>Right</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>a</span>
<a name="line-824"></a>                         <span class='hs-conid'>Left</span> <span class='hs-varid'>x</span>  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span>
<a name="line-825"></a>
<a name="line-826"></a>
</pre></body>
</html>

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