[270] | 1 | ##
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| 2 | # enumerator.rb Enumerator class
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| 3 | # See Copyright Notice in mruby.h
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| 4 |
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| 5 | ##
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| 6 | # A class which allows both internal and external iteration.
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| 7 | #
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| 8 | # An Enumerator can be created by the following methods.
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| 9 | # - {Kernel#to_enum}
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| 10 | # - {Kernel#enum_for}
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| 11 | # - {Enumerator#initialize Enumerator.new}
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| 12 | #
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| 13 | # Most methods have two forms: a block form where the contents
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| 14 | # are evaluated for each item in the enumeration, and a non-block form
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| 15 | # which returns a new Enumerator wrapping the iteration.
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| 16 | #
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| 17 | # enumerator = %w(one two three).each
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| 18 | # puts enumerator.class # => Enumerator
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| 19 | #
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| 20 | # enumerator.each_with_object("foo") do |item, obj|
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| 21 | # puts "#{obj}: #{item}"
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| 22 | # end
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| 23 | #
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| 24 | # # foo: one
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| 25 | # # foo: two
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| 26 | # # foo: three
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| 27 | #
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| 28 | # enum_with_obj = enumerator.each_with_object("foo")
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| 29 | # puts enum_with_obj.class # => Enumerator
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| 30 | #
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| 31 | # enum_with_obj.each do |item, obj|
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| 32 | # puts "#{obj}: #{item}"
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| 33 | # end
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| 34 | #
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| 35 | # # foo: one
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| 36 | # # foo: two
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| 37 | # # foo: three
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| 38 | #
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| 39 | # This allows you to chain Enumerators together. For example, you
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| 40 | # can map a list's elements to strings containing the index
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| 41 | # and the element as a string via:
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| 42 | #
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| 43 | # puts %w[foo bar baz].map.with_index { |w, i| "#{i}:#{w}" }
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| 44 | # # => ["0:foo", "1:bar", "2:baz"]
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| 45 | #
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| 46 | # An Enumerator can also be used as an external iterator.
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| 47 | # For example, Enumerator#next returns the next value of the iterator
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| 48 | # or raises StopIteration if the Enumerator is at the end.
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| 49 | #
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| 50 | # e = [1,2,3].each # returns an enumerator object.
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| 51 | # puts e.next # => 1
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| 52 | # puts e.next # => 2
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| 53 | # puts e.next # => 3
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| 54 | # puts e.next # raises StopIteration
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| 55 | #
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| 56 | # You can use this to implement an internal iterator as follows:
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| 57 | #
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| 58 | # def ext_each(e)
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| 59 | # while true
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| 60 | # begin
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| 61 | # vs = e.next_values
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| 62 | # rescue StopIteration
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| 63 | # return $!.result
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| 64 | # end
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| 65 | # y = yield(*vs)
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| 66 | # e.feed y
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| 67 | # end
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| 68 | # end
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| 69 | #
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| 70 | # o = Object.new
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| 71 | #
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| 72 | # def o.each
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| 73 | # puts yield
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| 74 | # puts yield(1)
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| 75 | # puts yield(1, 2)
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| 76 | # 3
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| 77 | # end
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| 78 | #
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| 79 | # # use o.each as an internal iterator directly.
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| 80 | # puts o.each {|*x| puts x; [:b, *x] }
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| 81 | # # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
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| 82 | #
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| 83 | # # convert o.each to an external iterator for
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| 84 | # # implementing an internal iterator.
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| 85 | # puts ext_each(o.to_enum) {|*x| puts x; [:b, *x] }
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| 86 | # # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
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| 87 | #
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| 88 | class Enumerator
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| 89 | include Enumerable
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| 90 |
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| 91 | ##
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| 92 | # @overload initialize(size = nil, &block)
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| 93 | # @overload initialize(obj, method = :each, *args)
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| 94 | #
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| 95 | # Creates a new Enumerator object, which can be used as an
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| 96 | # Enumerable.
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| 97 | #
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| 98 | # In the first form, iteration is defined by the given block, in
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| 99 | # which a "yielder" object, given as block parameter, can be used to
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| 100 | # yield a value by calling the +yield+ method (aliased as +<<+):
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| 101 | #
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| 102 | # fib = Enumerator.new do |y|
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| 103 | # a = b = 1
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| 104 | # loop do
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| 105 | # y << a
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| 106 | # a, b = b, a + b
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| 107 | # end
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| 108 | # end
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| 109 | #
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| 110 | # p fib.take(10) # => [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
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| 111 | #
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| 112 | def initialize(obj=nil, meth=:each, *args, &block)
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| 113 | if block_given?
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| 114 | obj = Generator.new(&block)
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| 115 | else
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| 116 | raise ArgumentError unless obj
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| 117 | end
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| 118 |
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| 119 | @obj = obj
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| 120 | @meth = meth
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| 121 | @args = args.dup
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| 122 | @fib = nil
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| 123 | @dst = nil
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| 124 | @lookahead = nil
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| 125 | @feedvalue = nil
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| 126 | @stop_exc = false
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| 127 | end
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| 128 | attr_accessor :obj, :meth, :args, :fib
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| 129 | private :obj, :meth, :args, :fib
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| 130 |
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| 131 | def initialize_copy(obj)
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| 132 | raise TypeError, "can't copy type #{obj.class}" unless obj.kind_of? Enumerator
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| 133 | raise TypeError, "can't copy execution context" if obj.fib
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| 134 | @obj = obj.obj
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| 135 | @meth = obj.meth
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| 136 | @args = obj.args
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| 137 | @fib = nil
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| 138 | @lookahead = nil
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| 139 | @feedvalue = nil
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| 140 | self
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| 141 | end
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| 142 |
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| 143 | ##
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| 144 | # call-seq:
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| 145 | # e.with_index(offset = 0) {|(*args), idx| ... }
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| 146 | # e.with_index(offset = 0)
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| 147 | #
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| 148 | # Iterates the given block for each element with an index, which
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| 149 | # starts from +offset+. If no block is given, returns a new Enumerator
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| 150 | # that includes the index, starting from +offset+
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| 151 | #
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| 152 | # +offset+:: the starting index to use
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| 153 | #
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| 154 | def with_index(offset=0)
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| 155 | return to_enum :with_index, offset unless block_given?
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[331] | 156 | offset = if offset.nil?
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| 157 | 0
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| 158 | elsif offset.respond_to?(:to_int)
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| 159 | offset.to_int
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| 160 | else
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| 161 | raise TypeError, "no implicit conversion of #{offset.class} into Integer"
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| 162 | end
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[270] | 163 |
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[331] | 164 | n = offset - 1
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| 165 | enumerator_block_call do |*i|
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[270] | 166 | n += 1
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[331] | 167 | yield i.__svalue, n
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[270] | 168 | end
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| 169 | end
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| 170 |
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| 171 | ##
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| 172 | # call-seq:
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| 173 | # e.each_with_index {|(*args), idx| ... }
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| 174 | # e.each_with_index
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| 175 | #
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| 176 | # Same as Enumerator#with_index(0), i.e. there is no starting offset.
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| 177 | #
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| 178 | # If no block is given, a new Enumerator is returned that includes the index.
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| 179 | #
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[331] | 180 | def each_with_index(&block)
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| 181 | with_index(0, &block)
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[270] | 182 | end
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| 183 |
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| 184 | ##
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| 185 | # call-seq:
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| 186 | # e.each_with_object(obj) {|(*args), obj| ... }
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| 187 | # e.each_with_object(obj)
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| 188 | # e.with_object(obj) {|(*args), obj| ... }
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| 189 | # e.with_object(obj)
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| 190 | #
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| 191 | # Iterates the given block for each element with an arbitrary object, +obj+,
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| 192 | # and returns +obj+
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| 193 | #
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| 194 | # If no block is given, returns a new Enumerator.
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| 195 | #
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| 196 | # @example
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| 197 | # to_three = Enumerator.new do |y|
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| 198 | # 3.times do |x|
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| 199 | # y << x
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| 200 | # end
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| 201 | # end
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| 202 | #
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| 203 | # to_three_with_string = to_three.with_object("foo")
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| 204 | # to_three_with_string.each do |x,string|
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| 205 | # puts "#{string}: #{x}"
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| 206 | # end
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| 207 | #
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| 208 | # # => foo:0
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| 209 | # # => foo:1
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| 210 | # # => foo:2
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| 211 | #
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| 212 | def with_object(object)
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| 213 | return to_enum(:with_object, object) unless block_given?
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| 214 |
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| 215 | enumerator_block_call do |i|
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| 216 | yield [i,object]
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| 217 | end
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| 218 | object
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| 219 | end
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| 220 |
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| 221 | def inspect
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| 222 | return "#<#{self.class}: uninitialized>" unless @obj
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| 223 |
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| 224 | if @args && @args.size > 0
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| 225 | args = @args.join(", ")
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| 226 | "#<#{self.class}: #{@obj}:#{@meth}(#{args})>"
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| 227 | else
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| 228 | "#<#{self.class}: #{@obj}:#{@meth}>"
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| 229 | end
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| 230 | end
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| 231 |
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| 232 | ##
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| 233 | # call-seq:
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| 234 | # enum.each { |elm| block } -> obj
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| 235 | # enum.each -> enum
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| 236 | # enum.each(*appending_args) { |elm| block } -> obj
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| 237 | # enum.each(*appending_args) -> an_enumerator
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| 238 | #
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| 239 | # Iterates over the block according to how this Enumerator was constructed.
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| 240 | # If no block and no arguments are given, returns self.
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| 241 | #
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| 242 | # === Examples
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| 243 | #
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| 244 | # "Hello, world!".scan(/\w+/) #=> ["Hello", "world"]
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| 245 | # "Hello, world!".to_enum(:scan, /\w+/).to_a #=> ["Hello", "world"]
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| 246 | # "Hello, world!".to_enum(:scan).each(/\w+/).to_a #=> ["Hello", "world"]
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| 247 | #
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| 248 | # obj = Object.new
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| 249 | #
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| 250 | # def obj.each_arg(a, b=:b, *rest)
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| 251 | # yield a
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| 252 | # yield b
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| 253 | # yield rest
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| 254 | # :method_returned
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| 255 | # end
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| 256 | #
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| 257 | # enum = obj.to_enum :each_arg, :a, :x
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| 258 | #
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| 259 | # enum.each.to_a #=> [:a, :x, []]
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| 260 | # enum.each.equal?(enum) #=> true
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| 261 | # enum.each { |elm| elm } #=> :method_returned
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| 262 | #
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| 263 | # enum.each(:y, :z).to_a #=> [:a, :x, [:y, :z]]
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| 264 | # enum.each(:y, :z).equal?(enum) #=> false
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| 265 | # enum.each(:y, :z) { |elm| elm } #=> :method_returned
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| 266 | #
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| 267 | def each(*argv, &block)
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| 268 | obj = self
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| 269 | if 0 < argv.length
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| 270 | obj = self.dup
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| 271 | args = obj.args
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| 272 | if !args.empty?
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| 273 | args = args.dup
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| 274 | args.concat argv
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| 275 | else
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| 276 | args = argv.dup
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| 277 | end
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| 278 | obj.args = args
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| 279 | end
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| 280 | return obj unless block_given?
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| 281 | enumerator_block_call(&block)
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| 282 | end
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| 283 |
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| 284 | def enumerator_block_call(&block)
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| 285 | @obj.__send__ @meth, *@args, &block
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| 286 | end
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| 287 | private :enumerator_block_call
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| 288 |
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| 289 | ##
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| 290 | # call-seq:
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| 291 | # e.next -> object
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| 292 | #
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| 293 | # Returns the next object in the enumerator, and move the internal position
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| 294 | # forward. When the position reached at the end, StopIteration is raised.
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| 295 | #
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| 296 | # === Example
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| 297 | #
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| 298 | # a = [1,2,3]
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| 299 | # e = a.to_enum
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| 300 | # p e.next #=> 1
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| 301 | # p e.next #=> 2
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| 302 | # p e.next #=> 3
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| 303 | # p e.next #raises StopIteration
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| 304 | #
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| 305 | # Note that enumeration sequence by +next+ does not affect other non-external
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| 306 | # enumeration methods, unless the underlying iteration methods itself has
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| 307 | # side-effect
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| 308 | #
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| 309 | def next
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| 310 | next_values.__svalue
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| 311 | end
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| 312 |
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| 313 | ##
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| 314 | # call-seq:
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| 315 | # e.next_values -> array
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| 316 | #
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| 317 | # Returns the next object as an array in the enumerator, and move the
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| 318 | # internal position forward. When the position reached at the end,
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| 319 | # StopIteration is raised.
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| 320 | #
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| 321 | # This method can be used to distinguish <code>yield</code> and <code>yield
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| 322 | # nil</code>.
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| 323 | #
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| 324 | # === Example
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| 325 | #
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| 326 | # o = Object.new
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| 327 | # def o.each
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| 328 | # yield
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| 329 | # yield 1
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| 330 | # yield 1, 2
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| 331 | # yield nil
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| 332 | # yield [1, 2]
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| 333 | # end
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| 334 | # e = o.to_enum
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| 335 | # p e.next_values
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| 336 | # p e.next_values
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| 337 | # p e.next_values
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| 338 | # p e.next_values
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| 339 | # p e.next_values
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| 340 | # e = o.to_enum
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| 341 | # p e.next
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| 342 | # p e.next
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| 343 | # p e.next
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| 344 | # p e.next
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| 345 | # p e.next
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| 346 | #
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| 347 | # ## yield args next_values next
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| 348 | # # yield [] nil
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| 349 | # # yield 1 [1] 1
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| 350 | # # yield 1, 2 [1, 2] [1, 2]
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| 351 | # # yield nil [nil] nil
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| 352 | # # yield [1, 2] [[1, 2]] [1, 2]
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| 353 | #
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| 354 | # Note that +next_values+ does not affect other non-external enumeration
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| 355 | # methods unless underlying iteration method itself has side-effect
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| 356 | #
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| 357 | def next_values
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| 358 | if @lookahead
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| 359 | vs = @lookahead
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| 360 | @lookahead = nil
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| 361 | return vs
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| 362 | end
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| 363 | raise @stop_exc if @stop_exc
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| 364 |
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| 365 | curr = Fiber.current
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| 366 |
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| 367 | if !@fib || !@fib.alive?
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| 368 | @dst = curr
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| 369 | @fib = Fiber.new do
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| 370 | result = each do |*args|
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| 371 | feedvalue = nil
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| 372 | Fiber.yield args
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| 373 | if @feedvalue
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| 374 | feedvalue = @feedvalue
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| 375 | @feedvalue = nil
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| 376 | end
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| 377 | feedvalue
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| 378 | end
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| 379 | @stop_exc = StopIteration.new "iteration reached an end"
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| 380 | @stop_exc.result = result
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| 381 | Fiber.yield nil
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| 382 | end
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| 383 | @lookahead = nil
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| 384 | end
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| 385 |
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| 386 | vs = @fib.resume curr
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| 387 | if @stop_exc
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| 388 | @fib = nil
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| 389 | @dst = nil
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| 390 | @lookahead = nil
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| 391 | @feedvalue = nil
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| 392 | raise @stop_exc
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| 393 | end
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| 394 | vs
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| 395 | end
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| 396 |
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| 397 | ##
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| 398 | # call-seq:
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| 399 | # e.peek -> object
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| 400 | #
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| 401 | # Returns the next object in the enumerator, but doesn't move the internal
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| 402 | # position forward. If the position is already at the end, StopIteration
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| 403 | # is raised.
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| 404 | #
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| 405 | # === Example
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| 406 | #
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| 407 | # a = [1,2,3]
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| 408 | # e = a.to_enum
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| 409 | # p e.next #=> 1
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| 410 | # p e.peek #=> 2
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| 411 | # p e.peek #=> 2
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| 412 | # p e.peek #=> 2
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| 413 | # p e.next #=> 2
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| 414 | # p e.next #=> 3
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| 415 | # p e.next #raises StopIteration
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| 416 | #
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| 417 | def peek
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| 418 | peek_values.__svalue
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| 419 | end
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| 420 |
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| 421 | ##
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| 422 | # call-seq:
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| 423 | # e.peek_values -> array
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| 424 | #
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| 425 | # Returns the next object as an array, similar to Enumerator#next_values, but
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| 426 | # doesn't move the internal position forward. If the position is already at
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| 427 | # the end, StopIteration is raised.
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| 428 | #
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| 429 | # === Example
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| 430 | #
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| 431 | # o = Object.new
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| 432 | # def o.each
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| 433 | # yield
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| 434 | # yield 1
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| 435 | # yield 1, 2
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| 436 | # end
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| 437 | # e = o.to_enum
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| 438 | # p e.peek_values #=> []
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| 439 | # e.next
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| 440 | # p e.peek_values #=> [1]
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| 441 | # p e.peek_values #=> [1]
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| 442 | # e.next
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| 443 | # p e.peek_values #=> [1, 2]
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| 444 | # e.next
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| 445 | # p e.peek_values # raises StopIteration
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| 446 | #
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| 447 | def peek_values
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| 448 | if @lookahead.nil?
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| 449 | @lookahead = next_values
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| 450 | end
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| 451 | @lookahead.dup
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| 452 | end
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| 453 |
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| 454 | ##
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| 455 | # call-seq:
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| 456 | # e.rewind -> e
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| 457 | #
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| 458 | # Rewinds the enumeration sequence to the beginning.
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| 459 | #
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| 460 | # If the enclosed object responds to a "rewind" method, it is called.
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| 461 | #
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| 462 | def rewind
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| 463 | @obj.rewind if @obj.respond_to? :rewind
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| 464 | @fib = nil
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| 465 | @dst = nil
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| 466 | @lookahead = nil
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| 467 | @feedvalue = nil
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| 468 | @stop_exc = false
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| 469 | self
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| 470 | end
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| 471 |
|
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| 472 | ##
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| 473 | # call-seq:
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| 474 | # e.feed obj -> nil
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| 475 | #
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| 476 | # Sets the value to be returned by the next yield inside +e+.
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| 477 | #
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| 478 | # If the value is not set, the yield returns nil.
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| 479 | #
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| 480 | # This value is cleared after being yielded.
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| 481 | #
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| 482 | # # Array#map passes the array's elements to "yield" and collects the
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| 483 | # # results of "yield" as an array.
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| 484 | # # Following example shows that "next" returns the passed elements and
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| 485 | # # values passed to "feed" are collected as an array which can be
|
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| 486 | # # obtained by StopIteration#result.
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| 487 | # e = [1,2,3].map
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| 488 | # p e.next #=> 1
|
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| 489 | # e.feed "a"
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| 490 | # p e.next #=> 2
|
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| 491 | # e.feed "b"
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| 492 | # p e.next #=> 3
|
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| 493 | # e.feed "c"
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| 494 | # begin
|
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| 495 | # e.next
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| 496 | # rescue StopIteration
|
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| 497 | # p $!.result #=> ["a", "b", "c"]
|
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| 498 | # end
|
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| 499 | #
|
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| 500 | # o = Object.new
|
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| 501 | # def o.each
|
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| 502 | # x = yield # (2) blocks
|
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| 503 | # p x # (5) => "foo"
|
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| 504 | # x = yield # (6) blocks
|
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| 505 | # p x # (8) => nil
|
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| 506 | # x = yield # (9) blocks
|
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| 507 | # p x # not reached w/o another e.next
|
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| 508 | # end
|
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| 509 | #
|
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| 510 | # e = o.to_enum
|
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| 511 | # e.next # (1)
|
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| 512 | # e.feed "foo" # (3)
|
---|
| 513 | # e.next # (4)
|
---|
| 514 | # e.next # (7)
|
---|
| 515 | # # (10)
|
---|
| 516 | #
|
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| 517 | def feed(value)
|
---|
| 518 | raise TypeError, "feed value already set" if @feedvalue
|
---|
| 519 | @feedvalue = value
|
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| 520 | nil
|
---|
| 521 | end
|
---|
| 522 |
|
---|
| 523 | # just for internal
|
---|
| 524 | class Generator
|
---|
[331] | 525 | include Enumerable
|
---|
[270] | 526 | def initialize(&block)
|
---|
| 527 | raise TypeError, "wrong argument type #{self.class} (expected Proc)" unless block.kind_of? Proc
|
---|
| 528 |
|
---|
| 529 | @proc = block
|
---|
| 530 | end
|
---|
| 531 |
|
---|
| 532 | def each(*args, &block)
|
---|
| 533 | args.unshift Yielder.new(&block)
|
---|
| 534 | @proc.call(*args)
|
---|
| 535 | end
|
---|
| 536 | end
|
---|
| 537 |
|
---|
| 538 | # just for internal
|
---|
| 539 | class Yielder
|
---|
| 540 | def initialize(&block)
|
---|
| 541 | raise LocalJumpError, "no block given" unless block_given?
|
---|
| 542 |
|
---|
| 543 | @proc = block
|
---|
| 544 | end
|
---|
| 545 |
|
---|
| 546 | def yield(*args)
|
---|
| 547 | @proc.call(*args)
|
---|
| 548 | end
|
---|
| 549 |
|
---|
| 550 | def << *args
|
---|
| 551 | self.yield(*args)
|
---|
| 552 | self
|
---|
| 553 | end
|
---|
| 554 | end
|
---|
| 555 | end
|
---|
| 556 |
|
---|
| 557 | module Kernel
|
---|
| 558 | ##
|
---|
| 559 | # call-seq:
|
---|
| 560 | # obj.to_enum(method = :each, *args) -> enum
|
---|
| 561 | # obj.enum_for(method = :each, *args) -> enum
|
---|
| 562 | # obj.to_enum(method = :each, *args) {|*args| block} -> enum
|
---|
| 563 | # obj.enum_for(method = :each, *args){|*args| block} -> enum
|
---|
| 564 | #
|
---|
| 565 | # Creates a new Enumerator which will enumerate by calling +method+ on
|
---|
| 566 | # +obj+, passing +args+ if any.
|
---|
| 567 | #
|
---|
| 568 | # If a block is given, it will be used to calculate the size of
|
---|
| 569 | # the enumerator without the need to iterate it (see Enumerator#size).
|
---|
| 570 | #
|
---|
| 571 | # === Examples
|
---|
| 572 | #
|
---|
| 573 | # str = "xyz"
|
---|
| 574 | #
|
---|
| 575 | # enum = str.enum_for(:each_byte)
|
---|
| 576 | # enum.each { |b| puts b }
|
---|
| 577 | # # => 120
|
---|
| 578 | # # => 121
|
---|
| 579 | # # => 122
|
---|
| 580 | #
|
---|
| 581 | # # protect an array from being modified by some_method
|
---|
| 582 | # a = [1, 2, 3]
|
---|
| 583 | # some_method(a.to_enum)
|
---|
| 584 | #
|
---|
| 585 | # It is typical to call to_enum when defining methods for
|
---|
| 586 | # a generic Enumerable, in case no block is passed.
|
---|
| 587 | #
|
---|
| 588 | # Here is such an example, with parameter passing and a sizing block:
|
---|
| 589 | #
|
---|
| 590 | # module Enumerable
|
---|
| 591 | # # a generic method to repeat the values of any enumerable
|
---|
| 592 | # def repeat(n)
|
---|
| 593 | # raise ArgumentError, "#{n} is negative!" if n < 0
|
---|
| 594 | # unless block_given?
|
---|
| 595 | # return to_enum(__method__, n) do # __method__ is :repeat here
|
---|
| 596 | # sz = size # Call size and multiply by n...
|
---|
| 597 | # sz * n if sz # but return nil if size itself is nil
|
---|
| 598 | # end
|
---|
| 599 | # end
|
---|
| 600 | # each do |*val|
|
---|
| 601 | # n.times { yield *val }
|
---|
| 602 | # end
|
---|
| 603 | # end
|
---|
| 604 | # end
|
---|
| 605 | #
|
---|
| 606 | # %i[hello world].repeat(2) { |w| puts w }
|
---|
| 607 | # # => Prints 'hello', 'hello', 'world', 'world'
|
---|
| 608 | # enum = (1..14).repeat(3)
|
---|
| 609 | # # => returns an Enumerator when called without a block
|
---|
| 610 | # enum.first(4) # => [1, 1, 1, 2]
|
---|
| 611 | #
|
---|
| 612 | def to_enum(meth=:each, *args)
|
---|
| 613 | Enumerator.new self, meth, *args
|
---|
| 614 | end
|
---|
| 615 | alias :enum_for :to_enum
|
---|
| 616 | end
|
---|
| 617 |
|
---|
| 618 | module Enumerable
|
---|
| 619 | # use Enumerator to use infinite sequence
|
---|
| 620 | def zip(*arg)
|
---|
| 621 | ary = []
|
---|
| 622 | arg = arg.map{|a|a.each}
|
---|
| 623 | i = 0
|
---|
| 624 | self.each do |*val|
|
---|
| 625 | a = []
|
---|
| 626 | a.push(val.__svalue)
|
---|
| 627 | idx = 0
|
---|
| 628 | while idx < arg.size
|
---|
| 629 | begin
|
---|
| 630 | a.push(arg[idx].next)
|
---|
| 631 | rescue StopIteration
|
---|
| 632 | a.push(nil)
|
---|
| 633 | end
|
---|
| 634 | idx += 1
|
---|
| 635 | end
|
---|
| 636 | ary.push(a)
|
---|
| 637 | i += 1
|
---|
| 638 | end
|
---|
| 639 | ary
|
---|
| 640 | end
|
---|
| 641 | end
|
---|