I guess I was just surprised to find this something that's more possible in Ruby-1.9. I'll still probably end up just translating to a proper parser but it was easy to use the regexp engine to start with. The below snippet is equivalent to my perl but does return the capture.

require 'pp'
re = %r{
  # Grammar rules go here
  (?:
    (?<thing>.+)
  ){0}

  # Invoke grammar here
  \g<thing>
}
m = re.match( 'text' )
puts m['thing'] # puts "text\n"
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