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##
# chain.rb Enumerator::Chain class
# See Copyright Notice in mruby.h
module Enumerable
def chain(*args)
Enumerator::Chain.new(self, *args)
end
end
class Enumerator
def +(other)
Chain.new(self, other)
end
class Chain
include Enumerable
def initialize(*args)
@enums = args
end
def each(&block)
return to_enum unless block_given?
@enums.each { |e| e.each(&block) }
self
end
def size
@enums.reduce(0) do |a, e|
return nil unless e.respond_to?(:size)
a + e.size
end
end
def rewind
i = @enums.size - 1
while 0 <= i
e = @enums[i]
e.rewind if e.respond_to?(:rewind)
i -= 1
end
self
end
def +(other)
self.class.new(self, other)
end
def inspect
"#<#{self.class}: #{@enums.inspect}>"
end
end
end
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