34 lines
615 B
Ruby
34 lines
615 B
Ruby
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# frozen_string_literal: true
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module MutualRecursion
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UNEXPECTED_TYPE = 'expected tail_call or terminal_value'
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class TailCall
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attr_reader :value, :block
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def initialize(value = nil, &block)
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@value = value
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@block = block
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end
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def invoke
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self.then do |tail|
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while tail.block
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tail = tail.block.call
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raise TypeError, UNEXPECTED_TYPE unless tail.is_a?(TailCall)
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end
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tail.value
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end
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end
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end
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end
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def tail_call
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MutualRecursion::TailCall.new { yield }
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end
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def terminal_value(value)
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MutualRecursion::TailCall.new(value)
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end
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