#!/usr/bin/perl
use strict;
use warnings;
use YAPE::Regex::Explain;
$\ = "\n*************\n";
# Your original
print YAPE::Regex::Explain->new(qr/[a-zA-Z]/)->explain;
print YAPE::Regex::Explain->new(qr/[a-zA-Z]+/)->explain;
print YAPE::Regex::Explain->new(qr/([a-zA-Z]+)/)->explain;
# The solution
print YAPE::Regex::Explain->new(qr/^([a-zA-Z]+)$/)->explain;