Contents

require 'enumerator'

if RUBY_VERSION < "1.9"

  module Enumerable

    class Enumerator

      alias :old_initialize :initialize

      # Provides the ruby-1.9 block form of Enumerator, where you can write:
      #
      #    obj = Enumerator.new do |yielder|
      #       .. do stuff
      #       yielder.yield data      # or: yielder << data
      #       .. etc
      #    end
      #
      # When obj.each is called, the block is run once. It should call
      # yielder.yield with each item it wishes to generate.
      #
      # Example:
      #
      #   fib = Enumerator.new { |y|
      #     a = b = 1
      #     loop {   
      #       y << a
      #       a, b = b, a + b
      #     }
      #   }  
      #
      #   assert_equal [1, 1, 2, 3, 5, 8, 13, 21, 34, 55], fib.take(10)
                                                    
      def initialize(*args, &block)
        if block_given?
          @body = block
          old_initialize(self, :_start)
        else
          old_initialize(*args)
        end
      end

      def _start(*args,&receiver) #:nodoc:
        @body.call(Yielder.new(receiver), *args)
      end

      # Wrapper to allow yielder.yield(output) or yielder << output
      # in the same way as ruby-1.9

      class Yielder #:nodoc:
        def initialize(proc)
          @proc = proc
        end
        def yield(*args)
          @proc[*args]
        end
        alias :<< :yield
      end
    end
    
  end

  # For ruby-1.9 compatibility, define Enumerator class at top level
  Enumerator = Enumerable::Enumerator unless defined? ::Enumerator

end # if RUBY_VERSION

Version data entries

4 entries across 4 versions & 1 rubygems

Version	Path
facets-2.6.0	lib/lore/facets/enumerator.rb
facets-2.5.0	lib/lore/facets/enumerator.rb
facets-2.5.1	lib/lore/facets/enumerator.rb
facets-2.5.2	lib/lore/facets/enumerator.rb