rule foo:w {
     $a := (\d+)
     =
     $b := (\w+)
     [ , | and ]
     $c := (\w+)
  };

  dump( rule=>"foo"; a=>7, b=>"hello", c=>"world" );

##</code><code>##

  \s+ 7 \s+ hello [ \s* , \s* | \s+ and \s+ ] world