class RDoc::Comment

def extract_call_seq
  # we must handle situations like the above followed by an unindented first
  # comment.  The difficulty is to make sure not to match lines starting
  # with ARGF at the same indent, but that are after the first description
  # paragraph.
  if /^(?<S> ((?!\n)\s)*+        (?# whitespaces except newline))
       :?call-seq:
         (?<B> \g<S>(?<N>\n|\z)  (?# trailing spaces))?
       (?<seq>
         (\g<S>(?!\w)\S.*\g<N>)*
         (?>
           (?<H> \g<S>\w+        (?# ' #   ARGF' in the example above))
           .*\g<N>)?
         (\g<S>\S.*\g<N>         (?# other non-blank line))*+
         (\g<B>+(\k<H>.*\g<N>    (?# ARGF.to_a lines))++)*+
       )
       (?m:^\s*$|\z)
      /x =~ @text
    seq = $~[:seq]
    all_start, all_stop = $~.offset(0)
    @text.slice! all_start...all_stop
    seq.gsub!(/^\s*/, '')
  end
end