/usr/lib/ruby/1.8/ramaze/snippets/ramaze/dictionary.rb

# = dictionary.rb
#
# == Copyright (c) 2005 Jan Molic, Thomas Sawyer
#
#   Ruby License
#
#   This module is free software. You may use, modify, and/or redistribute this
#   software under the same terms as Ruby.
#
#   This program is distributed in the hope that it will be useful, but WITHOUT
#   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
#   FOR A PARTICULAR PURPOSE.
#
# == Special Thanks
#
# Ported from OrderHash 2.0, Copyright (c) 2005 jan molic
#
# Thanks to Andrew Johnson for his suggestions and fixes of Hash[],
# merge, to_a, inspect and shift.
#
# == Authors & Contributors
#
# * Jan Molic
# * Thomas Sawyer

# Author::    Jan Molic
# Copyright:: Copyright (c) 2006 Jan Molic
# License::   Ruby License

# = Dictionary
#
# The Dictionary class is a Hash that preserves order.
# So it has some array-like extensions also. By defualt
# a Dictionary object preserves insertion order, but any
# order can be specified including alphabetical key order.
#
# == Usage
#
# Just require this file and use Dictionary instead of Hash.
#
#   # You can do simply
#   hsh = Dictionary.new
#   hsh['z'] = 1
#   hsh['a'] = 2
#   hsh['c'] = 3
#   p hsh.keys     #=> ['z','a','c']
#
#   # or using Dictionary[] method
#   hsh = Dictionary['z', 1, 'a', 2, 'c', 3]
#   p hsh.keys     #=> ['z','a','c']
#
#   # but this don't preserve order
#   hsh = Dictionary['z'=>1, 'a'=>2, 'c'=>3]
#   p hsh.keys     #=> ['a','c','z']
#
#   # Dictionary has useful extensions: push, pop and unshift
#   p hsh.push('to_end', 15)       #=> true, key added
#   p hsh.push('to_end', 30)       #=> false, already - nothing happen
#   p hsh.unshift('to_begin', 50)  #=> true, key added
#   p hsh.unshift('to_begin', 60)  #=> false, already - nothing happen
#   p hsh.keys                     #=> ["to_begin", "a", "c", "z", "to_end"]
#   p hsh.pop                      #=> ["to_end", 15], if nothing remains, return nil
#   p hsh.keys                     #=> ["to_begin", "a", "c", "z"]
#   p hsh.shift                    #=> ["to_begin", 30], if nothing remains, return nil
#
# == Usage Notes
#
# * You can use #order_by to set internal sort order.
# * #<< takes a two element [k,v] array and inserts.
# * Use ::auto which creates Dictionay sub-entries as needed.
# * And ::alpha which creates a new Dictionary sorted by key.

module Ramaze
  class Dictionary

    class << self

      #--
      # TODO is this needed? Doesn't the super class do this?
      #++

      def []( *args )
        hsh = new
        if Hash === args[0]
          hsh.replace(args[0])
        elsif (args.size % 2) != 0
          raise ArgumentError, "odd number of elements for Hash"
        else
          while !args.empty?
            hsh[args.shift] = args.shift
          end
        end
        hsh
      end

      # Like #new but the block sets the order.
      #
      def new_by( *args, &blk )
        new(*args).order_by(&blk)
      end

      # Alternate to #new which creates a dictionary sorted by key.
      #
      #   d = Dictionary.alpha
      #   d["z"] = 1
      #   d["y"] = 2
      #   d["x"] = 3
      #   d  #=> {"x"=>3,"y"=>2,"z"=>2}
      #
      # This is equivalent to:
      #
      #   Dictionary.new.order_by { |key,value| key }

      def alpha( *args, &block )
        new( *args, &block ).order_by_key
      end

      # Alternate to #new which auto-creates sub-dictionaries as needed.
      #
      #   d = Dictionary.auto
      #   d["a"]["b"]["c"] = "abc"  #=> { "a"=>{"b"=>{"c"=>"abc"}}}
      #
      def auto( *args )
        #AutoDictionary.new(*args)
        leet = lambda { |hsh, key| hsh[key] = new( &leet ) }
        new(*args, &leet)
      end
    end

    def initialize( *args, &blk )
      @order = []
      @order_by = nil
      @hash = Hash.new( *args, &blk )
    end

    def order
      reorder if @order_by
      @order
    end

    # Keep dictionary sorted by a specific sort order.

    def order_by( &block )
      @order_by = block
      order
      self
    end

    # Keep dictionary sorted by key.
    #
    #   d = Dictionary.new.order_by_key
    #   d["z"] = 1
    #   d["y"] = 2
    #   d["x"] = 3
    #   d  #=> {"x"=>3,"y"=>2,"z"=>2}
    #
    # This is equivalent to:
    #
    #   Dictionary.new.order_by { |key,value| key }
    #
    # The initializer Dictionary#alpha also provides this.

    def order_by_key
      @order_by = lambda { |k,v| k }
      order
      self
    end

    # Keep dictionary sorted by value.
    #
    #   d = Dictionary.new.order_by_value
    #   d["z"] = 1
    #   d["y"] = 2
    #   d["x"] = 3
    #   d  #=> {"x"=>3,"y"=>2,"z"=>2}
    #
    # This is equivalent to:
    #
    #   Dictionary.new.order_by { |key,value| value }

    def order_by_value
      @order_by = lambda { |k,v| v }
      order
      self
    end

    #

    def reorder
      if @order_by
        assoc = @order.collect{ |k| [k,@hash[k]] }.sort_by( &@order_by )
        @order = assoc.collect{ |k,v| k }
      end
      @order
    end

    #def ==( hsh2 )
    #  return false if @order != hsh2.order
    #  super hsh2
    #end

    def ==( hsh2 )
      if hsh2.is_a?( Dictionary )
        @order == hsh2.order &&
          @hash  == hsh2.instance_variable_get("@hash")
      else
        false
      end
    end

    def [] k
      @hash[ k ]
    end

    def fetch( k )
      @hash.fetch( k )
    end

    # Store operator.
    #
    #   h[key] = value
    #
    # Or with additional index.
    #
    #  h[key,index] = value

    def []=(k, i=nil, v=nil)
      if v
        insert(i,k,v)
      else
        store(k,i)
      end
    end

    def insert( i,k,v )
      @order.insert( i,k )
      @hash.store( k,v )
    end

    def store( a,b )
      @order.push( a ) unless @hash.has_key?( a )
      @hash.store( a,b )
    end

    def clear
      @order = []
      @hash.clear
    end

    def delete( key )
      @order.delete( key )
      @hash.delete( key )
    end

    def each_key
      order.each { |k| yield( k ) }
      self
    end

    def each_value
      order.each { |k| yield( @hash[k] ) }
      self
    end

    def each
      order.each { |k| yield( k,@hash[k] ) }
      self
    end
    alias each_pair each

    def delete_if
      order.clone.each { |k| delete k if yield }
      self
    end

    def values
      ary = []
      order.each { |k| ary.push @hash[k] }
      ary
    end

    def keys
      order
    end

    def invert
      hsh2 = self.class.new
      order.each { |k| hsh2[@hash[k]] = k }
      hsh2
    end

    def reject( &block )
      self.dup.delete_if(&block)
    end

    def reject!( &block )
      hsh2 = reject(&block)
      self == hsh2 ? nil : hsh2
    end

    def replace( hsh2 )
      @order = hsh2.order
      @hash = hsh2.hash
    end

    def shift
      key = order.first
      key ? [key,delete(key)] : super
    end

    def unshift( k,v )
      unless @hash.include?( k )
        @order.unshift( k )
        @hash.store( k,v )
        true
      else
        false
      end
    end

    def <<(kv)
      push(*kv)
    end

    def push( k,v )
      unless @hash.include?( k )
        @order.push( k )
        @hash.store( k,v )
        true
      else
        false
      end
    end

    def pop
      key = order.last
      key ? [key,delete(key)] : nil
    end

    def to_a
      ary = []
      each { |k,v| ary << [k,v] }
      ary
    end

    def to_s
      self.to_a.to_s
    end

    def inspect
      ary = []
      each {|k,v| ary << k.inspect + "=>" + v.inspect}
      '{' + ary.join(", ") + '}'
    end

    def dup
      self.class[*to_a.flatten]
    end

    def update( hsh2 )
      hsh2.each { |k,v| self[k] = v }
      reorder
      self
    end
    alias merge! update

    def merge( hsh2 )
      self.dup.update(hsh2)
    end

    def select
      ary = []
      each { |k,v| ary << [k,v] if yield k,v }
      ary
    end

    def find
      each{|k,v| return k, v if yield(k,v) }
      return nil
    end

    def first
      @hash[order.first]
    end

    def last
      @hash[order.last]
    end

    def length
      @order.length
    end
    alias size length

    def empty?
      @hash.empty?
    end

  end
end
libramaze-ruby1.8 2010.06.18-2 / usr / lib / ruby / 1.8 / ramaze / snippets / ramaze / dictionary.rb
