sub BUILDARGS {
    my $class = shift;
    my %args = ref $_[0] ?  %{$_[0]} : @_;
    $args{code} = uc $args{code} if exists $args{code};
    return \%args;
}

##</code><code>##

package UpperCaseDemo;
use Moose;
use Moose::Util::TypeConstraints;
with 'MooseX::Getopt';

subtype 'CurrencyCode'
    => as 'Str'
    => where { /^[A-Z]{3}$/ }
    => message { 'Currency codes should be three characters' },
    ;

coerce 'CurrencyCode'
    => from 'Str'
    => via { uc }
    ;

has 'code' => (
    is => 'ro', isa => 'CurrencyCode',
    coerce => 1,
);

1;

# -----------
# Usage: lookup --code abc or lookup --code ABC
#
package main;
my $cc = UpperCaseDemo->new_with_options();

print "code is ", $cc->code // 'not set', "\n";