use v5.10;
use warnings;


# SHOWCASE VARIOUS ERROR MESSAGES WITH A VERY UNWELL GRAMMAR

use Parse::RecDescent;

open (Parse::RecDescent::ERROR, ">-") or die;

$grammar =
q{
    <warn:3>

    typedef : a ... ...! ... b
    typedef : a ...!...!...!...! b
        | /type/ ident /has/ field(s) /end type/
            { $result = $item[2]; }
        | /type/ ident /is/ ident
            { $result = $item[2]; }
        | quasit(s)
        | quasit(-1..3)
        | quasit(..0)
        | field(?) field end
        | <error> quasit "here" ...!/why/

    Extend: extend

    Replace: replace
        $%^@#

    field   : /field/ ident /is/ ident
        | field quasit
        | !quasit(s?)
        !| #NOTHING


    typedef : whatever

    package somewhereelse

    !ident   : /[A-Za-z]\w*???/
            { $result = $item[1]; }

    quasit  : field
        | typedef
 };

new Parse::RecDescent ($grammar) || die "Bad grammar! No biscuit!\n";