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require_relative 'base'
class JsRegex
module Converter
#
# Template class implementation.
#
class BackreferenceConverter < JsRegex::Converter::Base
private
def convert_data
case subtype
when :name_ref then convert_name_ref
when :number, :number_ref, :number_rel_ref then convert_to_plain_num_ref
when :name_call, :number_call, :number_rel_call then convert_call
else # name_recursion_ref, number_recursion_ref, ...
warn_of_unsupported_feature
end
end
def convert_name_ref
if context.es_2018_or_higher?
# ES 2018+ supports named backrefs, but only the angled-bracket syntax
Node.new("\\k<#{expression.name}>", reference: new_position, type: :backref)
else
convert_to_plain_num_ref
end
end
def convert_to_plain_num_ref
position = new_position
Node.new("\\#{position}", reference: position, type: :backref)
end
def new_position
context.new_capturing_group_position(target_position)
end
def target_position
expression.referenced_expression.number
end
def convert_call
if expression.respond_to?(:number) && expression.number.equal?(0)
return warn_of_unsupported_feature('whole-pattern recursion')
end
context.increment_local_capturing_group_count
target_copy = expression.referenced_expression.unquantified_clone
# avoid "Duplicate capture group name" error in JS
target_copy.token = :capture if target_copy.is?(:named, :group)
convert_expression(target_copy)
end
end
end
end
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