Perl-ish Extended Regexes

" Perlish extended regexs
" Barry Arthur, Sep 2011

" Comments must start with two spaces and end with space and _

function! R(s)
  return substitute(substitute(a:s, '\s\{2,}".\{-}\s\+_', '', 'g'), '\s\+', '', 'g')
endfunction

function! TestThis(str)
  let my_extended_regex = '
        \ ^       " start of line    _
        \ \s*     " skip whitespace  _
        \ "\w\+"  " first word       _
        \'
  return matchstr(a:str, R(my_extended_regex))
endfunction

echo TestThis('"hello" world')