You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: ecma_regexp.rb
    path of file: ./repos/json_schemer/lib/json_schemer
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
module JSONSchemer
  class EcmaRegexp
    class Syntax < Regexp::Syntax::Base
      # regexp_parser >= 2.3.0 uses syntax classes directly instead of instances
      # :nocov:
      SYNTAX = respond_to?(:implements) ? self : new
      # :nocov:
      SYNTAX.implements :anchor, Anchor::Extended
      SYNTAX.implements :assertion, Assertion::All
      # 
    
      def ruby_equivalent(pattern)
        Regexp::Scanner.scan(pattern).map do |type, token, text|
          Syntax::SYNTAX.check!(*Syntax::SYNTAX.normalize(type, token))
          RUBY_EQUIVALENTS.dig(type, token) || text
        rescue Regexp::Syntax::NotImplementedError
          raise InvalidEcmaRegexp, "invalid token #{text.inspect} (#{type}:#{token}) in #{pattern.inspect}"
        end.join
      rescue Regexp::Scanner::ScannerError
        raise InvalidEcmaRegexp, "invalid pattern #{pattern.inspect}"
      end
    end