use strict;
use charnames ':full';
use Parse::RecDescent;
$::RD_TRACE = 1;
$::RD_HINT = 1;

my $parser = new Parse::RecDescent(<<'EOG') || die;
 ex1: "\N{DIAMOND OPERATOR}" {warn 'got it'} # fails despite 'use charnames'
 ex2: "\x{22c4}" {warn 'got it'} # always works
 ex3: /\p{Letter}/ {warn 'got letter'} # fails unless 'use charnames...'
EOG