Perl to Ruby Regular Expression Conversion

rubify_regexp.rb

  POSSIBLE_OPTIONS = "[misxp]"
  def rubify_regexp(l)
    re = l.gsub(/\(\?(#{POSSIBLE_OPTIONS}*)(?:-(#{POSSIBLE_OPTIONS}*))?:/) do |_|
      enabled = $1
      disabled = $2

      # Perl's `s` option is `m` in Ruby
      if enabled.include?('s') && !enabled.include?('m')
        enabled.sub!('s', 'm')
      else
        enabled.sub!('s', '')
      end

      # If Perl wanted to disable `s` then we need to disable `m`
      if disabled && disabled.include?('s')
        enabled.sub!('m', '')
      end

      "(?#{enabled}:"
    end
    Regexp.new(re)
  end