gistfile1.txt

use v6;

    # This fails.
    #→   ｢Method 'bar' not found for invocant of class 'Cursor'｣:
#my regex bar { <[\w]> };
#my regex foo { ^ <+ bar - [0..9]> <bar>* $ };

    # Using the character class directly of course works.
    #→  1: Nil
    #→  2: ｢asdf｣
    #→   foo => ｢asdf｣
my regex foo { ^ <+ [\w] - [0..9]> <[\w]>* $ };
say "1: ", "0sdf" ~~ /<foo>/;
say "2: ", "asdf" ~~ /<foo>/;


    # Using a grammar works too.
    #→  3: Nil
    #→  4: ｢asdf｣
    #→   bar => ｢s｣
    #→   bar => ｢d｣
    #→   bar => ｢f｣
grammar Goo {
    token bar { <[\w]> }
    token foo { <+ bar - [0..9]> <bar>* }
}
say "3: ", Goo.parse("0sdf", :rule('foo'));
say "4: ", Goo.parse("asdf", :rule('foo'));