Toby Inks' Type::Tiny suite, starting with Types::Standard.

#!/usr/bin/perl
use strict;
use warnings;
use Moo;
# Or Moose, or Mouse

use Types::Standard qw/ :all /;

has foo => (        is => 'ro', isa => Str,     required => 1 );
has bar => (        is => 'ro', isa => HashRef, required => 1 );
has flintstone => ( is => 'ro', isa => Enum[qw( Fred Wilma Pebbles Bam
+Bam )] );

# etc. . .
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Also see Type::Tiny and Type::Tiny::Manual to define your own constraints, and/or Type::Library to create a type library.

Hope this helps!