46 lines
1.0 KiB
Ruby
46 lines
1.0 KiB
Ruby
# A sequence of parslets, matched from left to right. Denoted by '>>'
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#
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# Example:
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#
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# str('a') >> str('b') # matches 'a', then 'b'
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#
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class Parslet::Atoms::Sequence < Parslet::Atoms::Base
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attr_reader :parslets
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def initialize(*parslets)
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super()
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@parslets = parslets
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@error_msgs = {
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:failed => "Failed to match sequence (#{self.inspect})"
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}
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end
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def >>(parslet)
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self.class.new(* @parslets+[parslet])
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end
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def try(source, context, consume_all)
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# Presize an array
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result = Array.new(parslets.size + 1)
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result[0] = :sequence
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parslets.each_with_index do |p, idx|
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child_consume_all = consume_all && (idx == parslets.size-1)
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success, value = p.apply(source, context, child_consume_all)
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unless success
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return context.err(self, source, @error_msgs[:failed], [value])
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end
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result[idx+1] = value
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end
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return succ(result)
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end
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precedence SEQUENCE
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def to_s_inner(prec)
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parslets.map { |p| p.to_s(prec) }.join(' ')
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end
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end
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