#!/usr/bin/perl

# make_parser.pl

use strict;
use warnings;

use Parse::RecDescent qw( );

my $grammar = <<'__END_OF_GRAMMAR__';
   {
      use strict;
      use warnings;
   }

   parse         : <skip:''> item_list /\Z/ { $item[2] }

   item_list     : <leftop: item ',' item> { $item[1] }

   item          : prefix bodies { [ $item[1], $item[2] ] }
                 |        bodies { [ undef,    $item[1] ] }

   bodies        : group { $item[1] }
                 | body  { [ $item[1] ] }

   prefix        : '<*' INTEGER '>' { $item[2] }

   group         : '(' <leftop: body ',' body> ')' { $item[2] }

   body          : NAME suffix(?) { [ $item[1], @{ $item[2] } ] }

   suffix        : '<' suffix_list '>' { $item[2] }

   suffix_list   : INTEGER suffix_list_[ $item[1] ]

   suffix_list_  : ',' <leftop: INTEGER ',' INTEGER>
                   { [ ',' => $arg[0], @{ $item[2] } ] }

                 | ':' <leftop: INTEGER ':' INTEGER>
                   { [ ':' => $arg[0], @{ $item[2] } ] }

                 | { [ '' => $arg[0] ] }

   INTEGER     : /0|[1-9][0-9]*/
   NAME        : /[A-Za-z][A-Za-z0-9_]*/

__END_OF_GRAMMAR__

Parse::RecDescent->Precompile($grammar, 'Grammar')
   or die("Bad grammar\n");