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<pre><a name="line-1"></a><span class='hs-comment'>-- |</span>
<a name="line-2"></a><span class='hs-comment'>-- Module: Data.Enumerator</span>
<a name="line-3"></a><span class='hs-comment'>-- Copyright: 2010-2011 John Millikin</span>
<a name="line-4"></a><span class='hs-comment'>-- License: MIT</span>
<a name="line-5"></a><span class='hs-comment'>--</span>
<a name="line-6"></a><span class='hs-comment'>-- Maintainer: jmillikin@gmail.com</span>
<a name="line-7"></a><span class='hs-comment'>-- Portability: portable</span>
<a name="line-8"></a><span class='hs-comment'>--</span>
<a name="line-9"></a><span class='hs-comment'>-- For compatibility reasons, this module should imported qualified:</span>
<a name="line-10"></a><span class='hs-comment'>--</span>
<a name="line-11"></a><span class='hs-comment'>-- @</span>
<a name="line-12"></a><span class='hs-comment'>-- import qualified Data.Enumerator as E</span>
<a name="line-13"></a><span class='hs-comment'>-- @</span>
<a name="line-14"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span>
<a name="line-15"></a> <span class='hs-layout'>(</span>
<a name="line-16"></a>
<a name="line-17"></a> <span class='hs-comment'>-- * Types</span>
<a name="line-18"></a> <span class='hs-conid'>Iteratee</span>
<a name="line-19"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Enumerator</span>
<a name="line-20"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Enumeratee</span>
<a name="line-21"></a>
<a name="line-22"></a> <span class='hs-comment'>-- * Running iteratees</span>
<a name="line-23"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>run</span>
<a name="line-24"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>run_</span>
<a name="line-25"></a>
<a name="line-26"></a> <span class='hs-comment'>-- * Operators</span>
<a name="line-27"></a> <span class='hs-comment'>-- | Compatibility note: Most of these will be obsoleted by</span>
<a name="line-28"></a> <span class='hs-comment'>-- version 0.5. Please make sure your @.cabal@ files have a</span>
<a name="line-29"></a> <span class='hs-comment'>-- @<0.5@ limit on the @enumerator@ dependency.</span>
<a name="line-30"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>>>==</span><span class='hs-layout'>)</span>
<a name="line-31"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>==<<</span><span class='hs-layout'>)</span>
<a name="line-32"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>$$</span><span class='hs-layout'>)</span>
<a name="line-33"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>>==></span><span class='hs-layout'>)</span>
<a name="line-34"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'><==<</span><span class='hs-layout'>)</span>
<a name="line-35"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>=$</span><span class='hs-layout'>)</span>
<a name="line-36"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>$=</span><span class='hs-layout'>)</span>
<a name="line-37"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>=$=</span><span class='hs-layout'>)</span>
<a name="line-38"></a>
<a name="line-39"></a> <span class='hs-comment'>-- * Error handling</span>
<a name="line-40"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>throwError</span>
<a name="line-41"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>catchError</span>
<a name="line-42"></a>
<a name="line-43"></a> <span class='hs-comment'>-- * Miscellaneous</span>
<a name="line-44"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>concatEnums</span>
<a name="line-45"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>joinI</span>
<a name="line-46"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>joinE</span>
<a name="line-47"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span><span class='hs-varop'>.</span><span class='hs-varid'>sequence</span>
<a name="line-48"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>isEOF</span>
<a name="line-49"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>tryIO</span>
<a name="line-50"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>liftTrans</span>
<a name="line-51"></a>
<a name="line-52"></a> <span class='hs-comment'>-- * Testing and debugging</span>
<a name="line-53"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>printChunks</span>
<a name="line-54"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>enumList</span>
<a name="line-55"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>enumLists</span>
<a name="line-56"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>runLists</span>
<a name="line-57"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>runLists_</span>
<a name="line-58"></a>
<a name="line-59"></a> <span class='hs-comment'>-- * Internal interfaces</span>
<a name="line-60"></a> <span class='hs-comment'>-- | This module export will be removed in version 0.5. If you</span>
<a name="line-61"></a> <span class='hs-comment'>-- depend on internal implementation details, please import</span>
<a name="line-62"></a> <span class='hs-comment'>-- @"Data.Enumerator.Internal"@ directly.</span>
<a name="line-63"></a> <span class='hs-layout'>,</span> <span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span>
<a name="line-64"></a>
<a name="line-65"></a> <span class='hs-comment'>-- Obsolete and pointless</span>
<a name="line-66"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>peek</span>
<a name="line-67"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span><span class='hs-varop'>.</span><span class='hs-varid'>last</span>
<a name="line-68"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span><span class='hs-varop'>.</span><span class='hs-varid'>length</span>
<a name="line-69"></a>
<a name="line-70"></a> <span class='hs-comment'>-- Legacy compatibility</span>
<a name="line-71"></a> <span class='hs-comment'>-- These legacy compatibility functions will be removed in</span>
<a name="line-72"></a> <span class='hs-comment'>-- version 0.5.</span>
<a name="line-73"></a> <span class='hs-layout'>,</span> <span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span><span class='hs-varop'>.</span><span class='hs-conid'>Compatibility</span>
<a name="line-74"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-75"></a>
<a name="line-76"></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'>Exc</span>
<a name="line-77"></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'>Monad</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>CM</span>
<a name="line-78"></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'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Class</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadIO</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftIO</span><span class='hs-layout'>)</span>
<a name="line-79"></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'>Trans</span><span class='hs-varop'>.</span><span class='hs-conid'>Class</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadTrans</span><span class='hs-layout'>,</span> <span class='hs-varid'>lift</span><span class='hs-layout'>)</span>
<a name="line-80"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Functor</span><span class='hs-varop'>.</span><span class='hs-conid'>Identity</span> <span class='hs-layout'>(</span><span class='hs-conid'>Identity</span><span class='hs-layout'>,</span> <span class='hs-varid'>runIdentity</span><span class='hs-layout'>)</span>
<a name="line-81"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span> <span class='hs-layout'>(</span><span class='hs-varid'>genericLength</span><span class='hs-layout'>,</span> <span class='hs-varid'>genericSplitAt</span><span class='hs-layout'>)</span>
<a name="line-82"></a>
<a name="line-83"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span><span class='hs-varop'>.</span><span class='hs-conid'>Compatibility</span>
<a name="line-84"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Enumerator</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span>
<a name="line-85"></a>
<a name="line-86"></a><a name="run"></a><span class='hs-comment'>-- | Run an iteratee until it finishes, and return either the final value</span>
<a name="line-87"></a><span class='hs-comment'>-- (if it succeeded) or the error (if it failed).</span>
<a name="line-88"></a><span class='hs-comment'>--</span>
<a name="line-89"></a><span class='hs-comment'>-- > import Data.Enumerator</span>
<a name="line-90"></a><span class='hs-comment'>-- > import Data.Enumerator.List as EL</span>
<a name="line-91"></a><span class='hs-comment'>-- ></span>
<a name="line-92"></a><span class='hs-comment'>-- > main = do</span>
<a name="line-93"></a><span class='hs-comment'>-- > result <- run (EL.iterate succ 'A' $$ EL.take 5)</span>
<a name="line-94"></a><span class='hs-comment'>-- > case result of</span>
<a name="line-95"></a><span class='hs-comment'>-- > Left exc -> putStrLn ("Got an exception: " ++ show exc)</span>
<a name="line-96"></a><span class='hs-comment'>-- > Right chars -> putStrLn ("Got characters: " ++ show chars)</span>
<a name="line-97"></a><span class='hs-definition'>run</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-98"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exc</span><span class='hs-varop'>.</span><span class='hs-conid'>SomeException</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-99"></a><span class='hs-definition'>run</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-100"></a> <span class='hs-varid'>mStep</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runIteratee</span> <span class='hs-varop'>$</span> <span class='hs-varid'>enumEOF</span> <span class='hs-varop'>==<<</span> <span class='hs-varid'>i</span>
<a name="line-101"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>mStep</span> <span class='hs-keyword'>of</span>
<a name="line-102"></a> <span class='hs-conid'>Error</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Left</span> <span class='hs-varid'>err</span>
<a name="line-103"></a> <span class='hs-conid'>Yield</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Right</span> <span class='hs-varid'>x</span>
<a name="line-104"></a> <span class='hs-conid'>Continue</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-str'>"run: divergent iteratee"</span>
<a name="line-105"></a>
<a name="line-106"></a><a name="run_"></a><span class='hs-comment'>-- | Like 'run', except errors are converted to exceptions and thrown.</span>
<a name="line-107"></a><span class='hs-comment'>-- Primarily useful for small scripts or other simple cases.</span>
<a name="line-108"></a><span class='hs-comment'>--</span>
<a name="line-109"></a><span class='hs-comment'>-- > import Data.Enumerator</span>
<a name="line-110"></a><span class='hs-comment'>-- > import Data.Enumerator.List as EL</span>
<a name="line-111"></a><span class='hs-comment'>-- ></span>
<a name="line-112"></a><span class='hs-comment'>-- > main = do</span>
<a name="line-113"></a><span class='hs-comment'>-- > chars <- run_ (EL.iterate succ 'A' $$ EL.take 5)</span>
<a name="line-114"></a><span class='hs-comment'>-- > putStrLn ("Got characters: " ++ show chars)</span>
<a name="line-115"></a><span class='hs-comment'>--</span>
<a name="line-116"></a><span class='hs-comment'>-- Since: 0.4.1</span>
<a name="line-117"></a><span class='hs-definition'>run_</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-118"></a><span class='hs-definition'>run_</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>run</span> <span class='hs-varid'>i</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>either</span> <span class='hs-conid'>Exc</span><span class='hs-varop'>.</span><span class='hs-varid'>throw</span> <span class='hs-varid'>return</span>
<a name="line-119"></a>
<a name="line-120"></a><a name="throwError"></a><span class='hs-comment'>-- | The moral equivalent of 'Exc.throwIO' for iteratees.</span>
<a name="line-121"></a><span class='hs-definition'>throwError</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-conid'>Exc</span><span class='hs-varop'>.</span><span class='hs-conid'>Exception</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-122"></a><span class='hs-definition'>throwError</span> <span class='hs-varid'>exc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>returnI</span> <span class='hs-layout'>(</span><span class='hs-conid'>Error</span> <span class='hs-layout'>(</span><span class='hs-conid'>Exc</span><span class='hs-varop'>.</span><span class='hs-varid'>toException</span> <span class='hs-varid'>exc</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-123"></a>
<a name="line-124"></a><a name="catchError"></a><span class='hs-comment'>-- | Runs the iteratee, and calls an exception handler if an 'Error' is</span>
<a name="line-125"></a><span class='hs-comment'>-- returned. By handling errors within the enumerator library, and requiring</span>
<a name="line-126"></a><span class='hs-comment'>-- all errors to be represented by 'Exc.SomeException', libraries with</span>
<a name="line-127"></a><span class='hs-comment'>-- varying error types can be easily composed.</span>
<a name="line-128"></a><span class='hs-comment'>--</span>
<a name="line-129"></a><span class='hs-comment'>-- WARNING: Within the error handler, it is difficult or impossible to know</span>
<a name="line-130"></a><span class='hs-comment'>-- how much input the original iteratee has consumed. Users are strongly</span>
<a name="line-131"></a><span class='hs-comment'>-- advised to wrap all uses of @catchError@ with an appropriate isolation</span>
<a name="line-132"></a><span class='hs-comment'>-- enumeratee, such as @Data.Enumerator.List.isolate@ or</span>
<a name="line-133"></a><span class='hs-comment'>-- @Data.Enumerator.Binary.isolate@, which will handle input framing even</span>
<a name="line-134"></a><span class='hs-comment'>-- in the face of unexpected errors.</span>
<a name="line-135"></a><span class='hs-comment'>--</span>
<a name="line-136"></a><span class='hs-comment'>-- Since: 0.1.1</span>
<a name="line-137"></a><span class='hs-definition'>catchError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span>
<a name="line-138"></a> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-139"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Exc</span><span class='hs-varop'>.</span><span class='hs-conid'>SomeException</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-140"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-141"></a><span class='hs-definition'>catchError</span> <span class='hs-varid'>i</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>i</span> <span class='hs-keyword'>where</span>
<a name="line-142"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>iter</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Iteratee</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-143"></a> <span class='hs-varid'>step</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runIteratee</span> <span class='hs-varid'>iter</span>
<a name="line-144"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>step</span> <span class='hs-keyword'>of</span>
<a name="line-145"></a> <span class='hs-conid'>Yield</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varid'>step</span>
<a name="line-146"></a> <span class='hs-conid'>Error</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runIteratee</span> <span class='hs-layout'>(</span><span class='hs-varid'>h</span> <span class='hs-varid'>err</span><span class='hs-layout'>)</span>
<a name="line-147"></a> <span class='hs-conid'>Continue</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Continue</span> <span class='hs-layout'>(</span><span class='hs-varid'>wrap</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-148"></a>
<a name="line-149"></a> <span class='hs-varid'>wrap</span> <span class='hs-varid'>k</span> <span class='hs-conid'>EOF</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Iteratee</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-150"></a> <span class='hs-varid'>res</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>run</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-conid'>EOF</span><span class='hs-layout'>)</span>
<a name="line-151"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>res</span> <span class='hs-keyword'>of</span>
<a name="line-152"></a> <span class='hs-conid'>Left</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runIteratee</span> <span class='hs-layout'>(</span><span class='hs-varid'>enumEOF</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>h</span> <span class='hs-varid'>err</span><span class='hs-layout'>)</span>
<a name="line-153"></a> <span class='hs-conid'>Right</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Yield</span> <span class='hs-varid'>b</span> <span class='hs-conid'>EOF</span><span class='hs-layout'>)</span>
<a name="line-154"></a>
<a name="line-155"></a> <span class='hs-varid'>wrap</span> <span class='hs-varid'>k</span> <span class='hs-varid'>stream</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Iteratee</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-156"></a> <span class='hs-varid'>step</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runIteratee</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>stream</span><span class='hs-layout'>)</span>
<a name="line-157"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>step</span> <span class='hs-keyword'>of</span>
<a name="line-158"></a> <span class='hs-conid'>Yield</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varid'>step</span>
<a name="line-159"></a> <span class='hs-conid'>Error</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-160"></a> <span class='hs-varid'>step'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runIteratee</span> <span class='hs-layout'>(</span><span class='hs-varid'>h</span> <span class='hs-varid'>err</span><span class='hs-layout'>)</span>
<a name="line-161"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>step'</span> <span class='hs-keyword'>of</span>
<a name="line-162"></a> <span class='hs-conid'>Continue</span> <span class='hs-varid'>k'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runIteratee</span> <span class='hs-layout'>(</span><span class='hs-varid'>k'</span> <span class='hs-varid'>stream</span><span class='hs-layout'>)</span>
<a name="line-163"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varid'>step'</span>
<a name="line-164"></a> <span class='hs-conid'>Continue</span> <span class='hs-varid'>k'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Continue</span> <span class='hs-layout'>(</span><span class='hs-varid'>wrap</span> <span class='hs-varid'>k'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-165"></a>
<a name="line-166"></a><a name="printChunks"></a><span class='hs-comment'>-- | Print chunks as they're received from the enumerator, optionally</span>
<a name="line-167"></a><span class='hs-comment'>-- printing empty chunks.</span>
<a name="line-168"></a><span class='hs-definition'>printChunks</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span> <span class='hs-conid'>Show</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-169"></a> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Bool</span> <span class='hs-comment'>-- ^ Print empty chunks</span>
<a name="line-170"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-171"></a><span class='hs-definition'>printChunks</span> <span class='hs-varid'>printEmpty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-varid'>loop</span> <span class='hs-keyword'>where</span>
<a name="line-172"></a> <span class='hs-varid'>loop</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-173"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>hide</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>null</span> <span class='hs-varid'>xs</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>not</span> <span class='hs-varid'>printEmpty</span>
<a name="line-174"></a> <span class='hs-conid'>CM</span><span class='hs-varop'>.</span><span class='hs-varid'>unless</span> <span class='hs-varid'>hide</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftIO</span> <span class='hs-layout'>(</span><span class='hs-varid'>print</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-175"></a> <span class='hs-varid'>continue</span> <span class='hs-varid'>loop</span>
<a name="line-176"></a>
<a name="line-177"></a> <span class='hs-varid'>loop</span> <span class='hs-conid'>EOF</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-178"></a> <span class='hs-varid'>liftIO</span> <span class='hs-layout'>(</span><span class='hs-varid'>putStrLn</span> <span class='hs-str'>"EOF"</span><span class='hs-layout'>)</span>
<a name="line-179"></a> <span class='hs-varid'>yield</span> <span class='hs-conid'>()</span> <span class='hs-conid'>EOF</span>
<a name="line-180"></a>
<a name="line-181"></a><a name="enumList"></a><span class='hs-comment'>-- | @'enumList' n xs@ enumerates /xs/ as a stream, passing /n/ inputs per</span>
<a name="line-182"></a><span class='hs-comment'>-- chunk. This is primarily useful for testing, debugging, and REPL</span>
<a name="line-183"></a><span class='hs-comment'>-- exploration.</span>
<a name="line-184"></a><span class='hs-comment'>--</span>
<a name="line-185"></a><span class='hs-comment'>-- Compatibility note: In version 0.5, 'enumList' will be changed to the</span>
<a name="line-186"></a><span class='hs-comment'>-- type:</span>
<a name="line-187"></a><span class='hs-comment'>--</span>
<a name="line-188"></a><span class='hs-comment'>-- > enumList :: Monad m => [a] -> Enumerator a m b</span>
<a name="line-189"></a><span class='hs-definition'>enumList</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Integer</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumerator</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-190"></a><span class='hs-definition'>enumList</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loop</span> <span class='hs-keyword'>where</span>
<a name="line-191"></a> <span class='hs-varid'>loop</span> <span class='hs-varid'>xs</span> <span class='hs-layout'>(</span><span class='hs-conid'>Continue</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span>
<a name="line-192"></a> <span class='hs-layout'>(</span><span class='hs-varid'>s1</span><span class='hs-layout'>,</span> <span class='hs-varid'>s2</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>genericSplitAt</span> <span class='hs-varid'>n</span> <span class='hs-varid'>xs</span>
<a name="line-193"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-varid'>s1</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>==</span> <span class='hs-varid'>loop</span> <span class='hs-varid'>s2</span>
<a name="line-194"></a> <span class='hs-varid'>loop</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>step</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>returnI</span> <span class='hs-varid'>step</span>
<a name="line-195"></a>
<a name="line-196"></a><a name="enumLists"></a><span class='hs-comment'>-- | @'enumLists' xs@ enumerates /xs/ as a stream, where each element is a</span>
<a name="line-197"></a><span class='hs-comment'>-- separate chunk. This is primarily useful for testing and debugging.</span>
<a name="line-198"></a><span class='hs-comment'>--</span>
<a name="line-199"></a><span class='hs-comment'>-- Since: 0.4.15</span>
<a name="line-200"></a><span class='hs-definition'>enumLists</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-keyglyph'>[</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumerator</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-201"></a><span class='hs-definition'>enumLists</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs</span><span class='hs-conop'>:</span><span class='hs-varid'>xss</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Continue</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>==</span> <span class='hs-varid'>enumLists</span> <span class='hs-varid'>xss</span>
<a name="line-202"></a><span class='hs-definition'>enumLists</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>step</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>returnI</span> <span class='hs-varid'>step</span>
<a name="line-203"></a>
<a name="line-204"></a><a name="runLists"></a><span class='hs-comment'>-- | Run an iteratee with the given input, and return either the final value</span>
<a name="line-205"></a><span class='hs-comment'>-- (if it succeeded) or the error (if it failed).</span>
<a name="line-206"></a><span class='hs-comment'>--</span>
<a name="line-207"></a><span class='hs-comment'>-- Since: 0.4.15</span>
<a name="line-208"></a><span class='hs-definition'>runLists</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-conid'>Identity</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Either</span> <span class='hs-conid'>Exc</span><span class='hs-varop'>.</span><span class='hs-conid'>SomeException</span> <span class='hs-varid'>b</span>
<a name="line-209"></a><span class='hs-definition'>runLists</span> <span class='hs-varid'>lists</span> <span class='hs-varid'>iter</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runIdentity</span> <span class='hs-layout'>(</span><span class='hs-varid'>run</span> <span class='hs-layout'>(</span><span class='hs-varid'>enumLists</span> <span class='hs-varid'>lists</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>iter</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-210"></a>
<a name="line-211"></a><a name="runLists_"></a><span class='hs-comment'>-- | Like 'runLists', except errors are converted to exceptions and thrown.</span>
<a name="line-212"></a><span class='hs-comment'>--</span>
<a name="line-213"></a><span class='hs-comment'>-- Since: 0.4.15</span>
<a name="line-214"></a><span class='hs-definition'>runLists_</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-conid'>Identity</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span>
<a name="line-215"></a><span class='hs-definition'>runLists_</span> <span class='hs-varid'>lists</span> <span class='hs-varid'>iter</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runIdentity</span> <span class='hs-layout'>(</span><span class='hs-varid'>run_</span> <span class='hs-layout'>(</span><span class='hs-varid'>enumLists</span> <span class='hs-varid'>lists</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>iter</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-216"></a>
<a name="line-217"></a><a name="concatEnums"></a><span class='hs-comment'>-- | Compose a list of 'Enumerator's using @('>==>').@</span>
<a name="line-218"></a><span class='hs-definition'>concatEnums</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Enumerator</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span>
<a name="line-219"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumerator</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-220"></a><span class='hs-definition'>concatEnums</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Prelude</span><span class='hs-varop'>.</span><span class='hs-varid'>foldl</span> <span class='hs-layout'>(</span><span class='hs-varop'>>==></span><span class='hs-layout'>)</span> <span class='hs-varid'>returnI</span>
<a name="line-221"></a>
<a name="line-222"></a><a name="joinI"></a><span class='hs-comment'>-- | &#x201c;Wraps&#x201d; an iteratee /inner/ in an enumeratee /wrapper/.</span>
<a name="line-223"></a><span class='hs-comment'>-- The resulting iteratee will consume /wrapper/&#x2019;s input type and</span>
<a name="line-224"></a><span class='hs-comment'>-- yield /inner/&#x2019;s output type.</span>
<a name="line-225"></a><span class='hs-comment'>--</span>
<a name="line-226"></a><span class='hs-comment'>-- See the documentation for ('=$').</span>
<a name="line-227"></a><span class='hs-comment'>--</span>
<a name="line-228"></a><span class='hs-comment'>-- @joinI (enum $$ iter) = enum =$ iter@</span>
<a name="line-229"></a><span class='hs-definition'>joinI</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Step</span> <span class='hs-varid'>a'</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-230"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-231"></a><span class='hs-definition'>joinI</span> <span class='hs-varid'>outer</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>outer</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>check</span> <span class='hs-keyword'>where</span>
<a name="line-232"></a> <span class='hs-varid'>check</span> <span class='hs-layout'>(</span><span class='hs-conid'>Continue</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span> <span class='hs-conid'>EOF</span> <span class='hs-varop'>>>==</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>s</span> <span class='hs-keyword'>of</span>
<a name="line-233"></a> <span class='hs-conid'>Continue</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-str'>"joinI: divergent iteratee"</span>
<a name="line-234"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>check</span> <span class='hs-varid'>s</span>
<a name="line-235"></a> <span class='hs-varid'>check</span> <span class='hs-layout'>(</span><span class='hs-conid'>Yield</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-236"></a> <span class='hs-varid'>check</span> <span class='hs-layout'>(</span><span class='hs-conid'>Error</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>throwError</span> <span class='hs-varid'>e</span>
<a name="line-237"></a>
<a name="line-238"></a><span class='hs-keyword'>infixr</span> <span class='hs-num'>0</span> <span class='hs-varop'>=$</span>
<a name="line-239"></a>
<a name="line-240"></a><a name="=$"></a><span class='hs-comment'>-- | &#x201c;Wraps&#x201d; an iteratee /inner/ in an enumeratee /wrapper/.</span>
<a name="line-241"></a><span class='hs-comment'>-- The resulting iteratee will consume /wrapper/&#x2019;s input type and</span>
<a name="line-242"></a><span class='hs-comment'>-- yield /inner/&#x2019;s output type.</span>
<a name="line-243"></a><span class='hs-comment'>--</span>
<a name="line-244"></a><span class='hs-comment'>-- Note: if the inner iteratee yields leftover input when it finishes,</span>
<a name="line-245"></a><span class='hs-comment'>-- that extra will be discarded.</span>
<a name="line-246"></a><span class='hs-comment'>--</span>
<a name="line-247"></a><span class='hs-comment'>-- As an example, consider an iteratee that converts a stream of UTF8-encoded</span>
<a name="line-248"></a><span class='hs-comment'>-- bytes into a single @Text@:</span>
<a name="line-249"></a><span class='hs-comment'>--</span>
<a name="line-250"></a><span class='hs-comment'>-- > consumeUTF8 :: Monad m => Iteratee ByteString m Text</span>
<a name="line-251"></a><span class='hs-comment'>--</span>
<a name="line-252"></a><span class='hs-comment'>-- It could be written with either 'joinI' or @(=$)@:</span>
<a name="line-253"></a><span class='hs-comment'>--</span>
<a name="line-254"></a><span class='hs-comment'>-- > import Data.Enumerator.Text as ET</span>
<a name="line-255"></a><span class='hs-comment'>-- ></span>
<a name="line-256"></a><span class='hs-comment'>-- > consumeUTF8 = joinI (decode utf8 $$ ET.consume)</span>
<a name="line-257"></a><span class='hs-comment'>-- > consumeUTF8 = decode utf8 =$ ET.consume</span>
<a name="line-258"></a><span class='hs-comment'>--</span>
<a name="line-259"></a><span class='hs-comment'>-- Since: 0.4.9</span>
<a name="line-260"></a><span class='hs-layout'>(</span><span class='hs-varop'>=$</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Enumeratee</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-261"></a><a name="enum"></a><span class='hs-definition'>enum</span> <span class='hs-varop'>=$</span> <span class='hs-varid'>iter</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>joinI</span> <span class='hs-layout'>(</span><span class='hs-varid'>enum</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>iter</span><span class='hs-layout'>)</span>
<a name="line-262"></a>
<a name="line-263"></a><a name="joinE"></a><span class='hs-comment'>-- | &#x201c;Wraps&#x201d; an enumerator /inner/ in an enumeratee /wrapper/.</span>
<a name="line-264"></a><span class='hs-comment'>-- The resulting enumerator will generate /wrapper/&#x2019;s output type.</span>
<a name="line-265"></a><span class='hs-comment'>--</span>
<a name="line-266"></a><span class='hs-comment'>-- See the documentation for ('$=').</span>
<a name="line-267"></a><span class='hs-comment'>--</span>
<a name="line-268"></a><span class='hs-comment'>-- @joinE enum enee = enum $= enee@</span>
<a name="line-269"></a><span class='hs-comment'>--</span>
<a name="line-270"></a><span class='hs-comment'>-- Since: 0.4.5</span>
<a name="line-271"></a><span class='hs-definition'>joinE</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span>
<a name="line-272"></a> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Enumerator</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Step</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-273"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumeratee</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-274"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumerator</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-275"></a><span class='hs-definition'>joinE</span> <span class='hs-varid'>enum</span> <span class='hs-varid'>enee</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Iteratee</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-276"></a> <span class='hs-varid'>step</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runIteratee</span> <span class='hs-layout'>(</span><span class='hs-varid'>enumEOF</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>enum</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>enee</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-277"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>step</span> <span class='hs-keyword'>of</span>
<a name="line-278"></a> <span class='hs-conid'>Error</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>Error</span> <span class='hs-varid'>err</span><span class='hs-layout'>)</span>
<a name="line-279"></a> <span class='hs-conid'>Yield</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-280"></a> <span class='hs-conid'>Continue</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-str'>"joinE: divergent iteratee"</span>
<a name="line-281"></a>
<a name="line-282"></a><span class='hs-keyword'>infixl</span> <span class='hs-num'>1</span> <span class='hs-varop'>$=</span>
<a name="line-283"></a>
<a name="line-284"></a><a name="$="></a><span class='hs-comment'>-- | &#x201c;Wraps&#x201d; an enumerator /inner/ in an enumeratee /wrapper/.</span>
<a name="line-285"></a><span class='hs-comment'>-- The resulting enumerator will generate /wrapper/&#x2019;s output type.</span>
<a name="line-286"></a><span class='hs-comment'>--</span>
<a name="line-287"></a><span class='hs-comment'>-- As an example, consider an enumerator that yields line character counts</span>
<a name="line-288"></a><span class='hs-comment'>-- for a text file (e.g. for source code readability checking):</span>
<a name="line-289"></a><span class='hs-comment'>--</span>
<a name="line-290"></a><span class='hs-comment'>-- > enumFileCounts :: FilePath -> Enumerator Int IO b</span>
<a name="line-291"></a><span class='hs-comment'>--</span>
<a name="line-292"></a><span class='hs-comment'>-- It could be written with either 'joinE' or @($=)@:</span>
<a name="line-293"></a><span class='hs-comment'>--</span>
<a name="line-294"></a><span class='hs-comment'>-- > import Data.Text as T</span>
<a name="line-295"></a><span class='hs-comment'>-- > import Data.Enumerator.List as EL</span>
<a name="line-296"></a><span class='hs-comment'>-- > import Data.Enumerator.Text as ET</span>
<a name="line-297"></a><span class='hs-comment'>-- ></span>
<a name="line-298"></a><span class='hs-comment'>-- > enumFileCounts path = joinE (enumFile path) (EL.map T.length)</span>
<a name="line-299"></a><span class='hs-comment'>-- > enumFileCounts path = enumFile path $= EL.map T.length</span>
<a name="line-300"></a><span class='hs-comment'>--</span>
<a name="line-301"></a><span class='hs-comment'>-- Compatibility note: in version 0.4.15, the associativity of @($=)@ was</span>
<a name="line-302"></a><span class='hs-comment'>-- changed from @infixr 0@ to @infixl 1@.</span>
<a name="line-303"></a><span class='hs-comment'>--</span>
<a name="line-304"></a><span class='hs-comment'>-- Since: 0.4.9</span>
<a name="line-305"></a><span class='hs-layout'>(</span><span class='hs-varop'>$=</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span>
<a name="line-306"></a> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Enumerator</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Step</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-307"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumeratee</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-308"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumerator</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-309"></a><span class='hs-layout'>(</span><span class='hs-varop'>$=</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>joinE</span>
<a name="line-310"></a>
<a name="line-311"></a><a name="=$="></a><span class='hs-comment'>-- | Composes two enumeratees.</span>
<a name="line-312"></a><span class='hs-comment'>--</span>
<a name="line-313"></a><span class='hs-comment'>-- Note that if the inner enumeratee yields left-over input, this will be</span>
<a name="line-314"></a><span class='hs-comment'>-- discarded.</span>
<a name="line-315"></a><span class='hs-comment'>--</span>
<a name="line-316"></a><span class='hs-comment'>-- Example: converting bytes into lower-case text:</span>
<a name="line-317"></a><span class='hs-comment'>--</span>
<a name="line-318"></a><span class='hs-comment'>-- > import Data.ByteString</span>
<a name="line-319"></a><span class='hs-comment'>-- > import Data.Text</span>
<a name="line-320"></a><span class='hs-comment'>-- > import Data.Enumerator.List as EnumList</span>
<a name="line-321"></a><span class='hs-comment'>-- > import Data.Enumerator.Text</span>
<a name="line-322"></a><span class='hs-comment'>-- ></span>
<a name="line-323"></a><span class='hs-comment'>-- > decodeAndLower :: Monad m => Enumeratee ByteString Text m b</span>
<a name="line-324"></a><span class='hs-comment'>-- > decodeAndLower = decode utf8 =$= EnumList.map toLower</span>
<a name="line-325"></a><span class='hs-comment'>--</span>
<a name="line-326"></a><span class='hs-comment'>-- Since: 0.4.17</span>
<a name="line-327"></a><span class='hs-layout'>(</span><span class='hs-varop'>=$=</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span>
<a name="line-328"></a> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Enumeratee</span> <span class='hs-varid'>a1</span> <span class='hs-varid'>a2</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Step</span> <span class='hs-varid'>a3</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-329"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumeratee</span> <span class='hs-varid'>a2</span> <span class='hs-varid'>a3</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-330"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumeratee</span> <span class='hs-varid'>a1</span> <span class='hs-varid'>a3</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-331"></a><a name="e1"></a><span class='hs-definition'>e1</span> <span class='hs-varop'>=$=</span> <span class='hs-varid'>e2</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>joinI</span> <span class='hs-layout'>(</span><span class='hs-varid'>e1</span> <span class='hs-varop'>$$</span> <span class='hs-varid'>e2</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-332"></a>
<a name="line-333"></a><span class='hs-keyword'>infixl</span> <span class='hs-num'>1</span> <span class='hs-varop'>=$=</span>
<a name="line-334"></a>
<a name="line-335"></a><a name="sequence"></a><span class='hs-comment'>-- | Feeds outer input elements into the provided iteratee until it yields</span>
<a name="line-336"></a><span class='hs-comment'>-- an inner input, passes that to the inner iteratee, and then loops.</span>
<a name="line-337"></a><span class='hs-definition'>sequence</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>m</span> <span class='hs-varid'>ai</span>
<a name="line-338"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Enumeratee</span> <span class='hs-varid'>ao</span> <span class='hs-varid'>ai</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-339"></a><span class='hs-definition'>sequence</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>loop</span> <span class='hs-keyword'>where</span>
<a name="line-340"></a> <span class='hs-varid'>loop</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>checkDone</span> <span class='hs-varid'>check</span>
<a name="line-341"></a> <span class='hs-varid'>check</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>isEOF</span> <span class='hs-varop'>>>=</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>f</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>if</span> <span class='hs-varid'>f</span>
<a name="line-342"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>yield</span> <span class='hs-layout'>(</span><span class='hs-conid'>Continue</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-conid'>EOF</span>
<a name="line-343"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>step</span> <span class='hs-varid'>k</span>
<a name="line-344"></a> <span class='hs-varid'>step</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>i</span> <span class='hs-varop'>>>=</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>v</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>v</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>==</span> <span class='hs-varid'>loop</span>
<a name="line-345"></a>
<a name="line-346"></a><a name="isEOF"></a><span class='hs-comment'>-- | Check whether a stream has reached EOF. Note that if the stream is not</span>
<a name="line-347"></a><span class='hs-comment'>-- at EOF, @isEOF@ may cause data to be read from the enumerator.</span>
<a name="line-348"></a><span class='hs-definition'>isEOF</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-conid'>Bool</span>
<a name="line-349"></a><span class='hs-definition'>isEOF</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>s</span> <span class='hs-keyword'>of</span>
<a name="line-350"></a> <span class='hs-conid'>EOF</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>yield</span> <span class='hs-conid'>True</span> <span class='hs-varid'>s</span>
<a name="line-351"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>yield</span> <span class='hs-conid'>False</span> <span class='hs-varid'>s</span>
<a name="line-352"></a>
<a name="line-353"></a><a name="tryIO"></a><span class='hs-comment'>-- | Try to run an IO computation. If it throws an exception, the exception</span>
<a name="line-354"></a><span class='hs-comment'>-- is caught and passed to 'throwError'.</span>
<a name="line-355"></a><span class='hs-comment'>--</span>
<a name="line-356"></a><span class='hs-comment'>-- Since: 0.4.9</span>
<a name="line-357"></a><span class='hs-definition'>tryIO</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-358"></a><span class='hs-definition'>tryIO</span> <span class='hs-varid'>io</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Iteratee</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-359"></a> <span class='hs-varid'>tried</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>liftIO</span> <span class='hs-layout'>(</span><span class='hs-conid'>Exc</span><span class='hs-varop'>.</span><span class='hs-varid'>try</span> <span class='hs-varid'>io</span><span class='hs-layout'>)</span>
<a name="line-360"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>tried</span> <span class='hs-keyword'>of</span>
<a name="line-361"></a> <span class='hs-conid'>Right</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Yield</span> <span class='hs-varid'>b</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-362"></a> <span class='hs-conid'>Left</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Error</span> <span class='hs-varid'>err</span>
<a name="line-363"></a>
<a name="line-364"></a><a name="liftTrans"></a><span class='hs-comment'>-- | Lift an 'Iteratee' onto a monad transformer, re-wrapping its</span>
<a name="line-365"></a><span class='hs-comment'>-- inner monadic values.</span>
<a name="line-366"></a><span class='hs-comment'>--</span>
<a name="line-367"></a><span class='hs-comment'>-- Since: 0.1.1</span>
<a name="line-368"></a><span class='hs-definition'>liftTrans</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-conid'>MonadTrans</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</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'>=></span>
<a name="line-369"></a> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</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-varid'>b</span>
<a name="line-370"></a><span class='hs-definition'>liftTrans</span> <span class='hs-varid'>iter</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Iteratee</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-371"></a> <span class='hs-varid'>step</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>lift</span> <span class='hs-layout'>(</span><span class='hs-varid'>runIteratee</span> <span class='hs-varid'>iter</span><span class='hs-layout'>)</span>
<a name="line-372"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>step</span> <span class='hs-keyword'>of</span>
<a name="line-373"></a> <span class='hs-conid'>Yield</span> <span class='hs-varid'>x</span> <span class='hs-varid'>cs</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Yield</span> <span class='hs-varid'>x</span> <span class='hs-varid'>cs</span>
<a name="line-374"></a> <span class='hs-conid'>Error</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Error</span> <span class='hs-varid'>err</span>
<a name="line-375"></a> <span class='hs-conid'>Continue</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Continue</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftTrans</span> <span class='hs-varop'>.</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>
<a name="line-376"></a>
<a name="line-377"></a><a name="peek"></a><span class='hs-comment'>-- | Peek at the next element in the stream, or 'Nothing' if the stream</span>
<a name="line-378"></a><span class='hs-comment'>-- has ended.</span>
<a name="line-379"></a><span class='hs-definition'>peek</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</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-380"></a><span class='hs-definition'>peek</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-varid'>loop</span> <span class='hs-keyword'>where</span>
<a name="line-381"></a> <span class='hs-varid'>loop</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-varid'>loop</span>
<a name="line-382"></a> <span class='hs-varid'>loop</span> <span class='hs-varid'>chunk</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-keyword'>_</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>yield</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-varid'>chunk</span>
<a name="line-383"></a> <span class='hs-varid'>loop</span> <span class='hs-conid'>EOF</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>yield</span> <span class='hs-conid'>Nothing</span> <span class='hs-conid'>EOF</span>
<a name="line-384"></a>
<a name="line-385"></a><a name="last"></a><span class='hs-comment'>-- | Get the last element in the stream, or 'Nothing' if the stream</span>
<a name="line-386"></a><span class='hs-comment'>-- has ended.</span>
<a name="line-387"></a><span class='hs-comment'>--</span>
<a name="line-388"></a><span class='hs-comment'>-- Consumes the entire stream.</span>
<a name="line-389"></a><span class='hs-definition'>last</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</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-390"></a><span class='hs-definition'>last</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-varid'>loop</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-391"></a> <span class='hs-varid'>loop</span> <span class='hs-varid'>ret</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-varop'>.</span> <span class='hs-varid'>loop</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>xs</span> <span class='hs-keyword'>of</span>
<a name="line-392"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>ret</span>
<a name="line-393"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-conid'>Prelude</span><span class='hs-varop'>.</span><span class='hs-varid'>last</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-394"></a> <span class='hs-varid'>loop</span> <span class='hs-varid'>ret</span> <span class='hs-conid'>EOF</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>yield</span> <span class='hs-varid'>ret</span> <span class='hs-conid'>EOF</span>
<a name="line-395"></a>
<a name="line-396"></a><a name="length"></a><span class='hs-comment'>-- | Get how many elements remained in the stream.</span>
<a name="line-397"></a><span class='hs-comment'>--</span>
<a name="line-398"></a><span class='hs-comment'>-- Consumes the entire stream.</span>
<a name="line-399"></a><span class='hs-definition'>length</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Iteratee</span> <span class='hs-varid'>a</span> <span class='hs-varid'>m</span> <span class='hs-conid'>Integer</span>
<a name="line-400"></a><span class='hs-definition'>length</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-varid'>loop</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-401"></a> <span class='hs-varid'>len</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>genericLength</span>
<a name="line-402"></a> <span class='hs-varid'>loop</span> <span class='hs-varid'>n</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chunks</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-varid'>loop</span> <span class='hs-layout'>(</span><span class='hs-varid'>n</span> <span class='hs-varop'>+</span> <span class='hs-varid'>len</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-403"></a> <span class='hs-varid'>loop</span> <span class='hs-varid'>n</span> <span class='hs-conid'>EOF</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>yield</span> <span class='hs-varid'>n</span> <span class='hs-conid'>EOF</span>
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