#!/usr/bin/perl -slw

use strict;
use re 'debug';

sub mysub {
    die 'single word expected' if (my $name = shift @_)  =~ /^\w+$/;
    die 'single word expected' if (my $value = shift @_) =~ /^\w+$/;
}

my $str = 'abc def';
$str =~ /(\w+)\s+(\w+)/;
print "\(&mysub(<$1> <$2>))";