01-compile-slurpy-dict.pl

# This is the old way to do it.

use v5.10;
use strict;
use warnings;
use Test::More;
use Test::Fatal;

use Types::Standard -all;
use Type::Params -all;

sub format_iso_date {
	state $check = compile( slurpy Dict[ year=>Int, month=>Int, day=>Int ] );
	
	my ($args) = $check->(@_);
	
	return sprintf(
		'%04d-%02d-%02d',
		$args->{year},
		$args->{month},
		$args->{day},
	);
}

is(
	format_iso_date( year=>2017, month=>5, day=>5 ),
	'2017-05-05',
	'format_iso_date works',
);

use Math::Trig qw(pi);

like(
	exception { format_iso_date( year=>2017, month=>pi, day=>5 ) },
	qr/Reference .+ did not pass type constraint "Dict.+"/,
	'months cannot be transcendental numbers',
);

done_testing;

02-compile-named.pl

# This is the new way to do it.

use v5.10;
use strict;
use warnings;
use Test::More;
use Test::Fatal;

use Types::Standard -all;
use Type::Params -all;

sub format_iso_date {
	state $check = compile_named( year=>Int, month=>Int, day=>Int );
	
	my $args = $check->(@_);
	
	return sprintf(
		'%04d-%02d-%02d',
		$args->{year},
		$args->{month},
		$args->{day},
	);
}

is(
	format_iso_date( year=>2017, month=>5, day=>5 ),
	'2017-05-05',
	'format_iso_date works',
);

is(
	format_iso_date( { year=>2017, month=>5, day=>5 } ),
	'2017-05-05',
	'... and accepts hashrefs',
);

use Math::Trig qw(pi);

like(
	exception { format_iso_date( year=>2017, month=>pi, day=>5 ) },
	qr/Value "3.14159.+" did not pass type constraint "Int"/,
	'months cannot be transcendental numbers',
);

done_testing;