First read Type::Tiny::Manual::Moo, Type::Tiny::Manual::Moo2, and Type::Tiny::Manual::Moo3. Everything in
those parts of the manual should work exactly the same in Moose.
This part of the manual will focus on Moose-specifics.
WhyUseType::TinyAtAll?
Moose does have a built-in type constraint system which is fairly convenient to use, but there are
several reasons you should consider using Type::Tiny instead.
• Type::Tiny type constraints will usually be faster than Moose built-ins. Even without Type::Tiny::XS
installed, Type::Tiny usually produces more efficient inline code than Moose. Coercions will usually
be a lot faster.
• Type::Tiny provides helpful methods like "where" and "plus_coercions" that allow type constraints and
coercions to be easily tweaked on a per-attribute basis.
Something like this is much harder to do with plain Moose types:
has name => (
is => "ro",
isa => Str->plus_coercions(
ArrayRef[Str], sub { join " ", @$_ },
),
coerce => 1,
);
Moose tends to encourage defining coercions globally, so if you wanted one Str attribute to be able
to coerce from ArrayRef[Str], then allStr attributes would coerce from ArrayRef[Str], and they'd all
do that coercion in the same way. (Even if it might make sense to join by a space in some places, a
comma in others, and a line break in others!)
• Type::Tiny provides automatic deep coercions, so if type Xyz has a coercion, the following should
"just work":
has xyzlist => ( is => 'ro', isa => ArrayRef[Xyz], coerce => 1 );
• Type::Tiny offers a wider selection of built-in types.
• By using Type::Tiny, you can use the same type constraints and coercions for attributes and method
parameters, in Moose and non-Moose code.
Type::Utils
If you've used Moose::Util::TypeConstraints, you may be accustomed to using a DSL for declaring type
constraints:
use Moose::Util::TypeConstraints;
subtype 'Natural',
as 'Int',
where { $_ > 0 };
There's a module called Type::Utils that provides a very similar DSL for declaring types in
Type::Library-based type libraries.
package My::Types {
use Type::Library -base;
use Type::Utils;
use Types::Standard qw( Int );
declare 'Natural',
as Int,
where { $_ > 0 };
}
Personally I prefer the more object-oriented way to declare types though.
Since Type::Library 1.012, a shortcut has been available for importing Type::Library and Type::Utils at
the same time:
package MyType {
use Type::Library -base, -utils;
...;
}
In Moose you might also declare types like this within classes and roles too. Unlike Moose, Type::Tiny
doesn't keep types in a single global flat namespace, so this doesn't work quite the same with
Type::Utils. It still creates the type, but it doesn't store it in any type library; the type is
returned.
package My::Class {
use Moose;
use Type::Utils;
use Types::Standard qw( Int );
my $Natural = # store type in a variable
declare 'Natural',
as Int,
where { $_ > 0 };
has number => ( is => 'ro', isa => $Natural );
}
But really, isn't the object-oriented way cleaner?
package My::Class {
use Moose;
use Types::Standard qw( Int );
has number => (
is => 'ro',
isa => Int->where('$_ > 0'),
);
}
Type::TinyandMooseX::Types
Types::Standard should be a drop-in replacement for MooseX::Types. And Types::Common::Numeric and
Types::Common::String should easily replace MooseX::Types::Common::Numeric and
MooseX::Types::Common::String.
That said, if you do with to use a mixture of Type::Tiny and MooseX::Types, they should fit together
pretty seamlessly.
use Types::Standard qw( ArrayRef );
use MooseX::Types::Common::Numeric qw( PositiveInt );
# this should just work
my $list_of_nums = ArrayRef[PositiveInt];
# and this
my $list_or_num = ArrayRef | PositiveInt;
"-moose"ImportParameter
If you have read this far in the manual, you will know that this is the usual way to import type
constraints:
use Types::Standard qw( Int );
And the "Int" which is imported is a function that takes no arguments and returns the Int type
constraint, which is a blessed object in the Type::Tiny class.
Type::Tiny mocks the Moose::Meta::TypeConstraint API so well that most Moose and MooseX code will not be
able to tell the difference.
But what if you need a real Moose::Meta::TypeConstraint object?
use Types::Standard -moose, qw( Int );
Now the "Int" function imported will return a genuine native Moose type constraint.
This flag is mostly a throwback from when Type::Tiny native objects didn't directly work in Moose. In
99.9% of cases, there is no reason to use it and plenty of reasons not to. (Moose native type constraints
don't offer helpful methods like "plus_coercions" and "where".)
"moose_type"Method
Another quick way to get a native Moose type constraint object from a Type::Tiny object is to call the
"moose_type" method:
use Types::Standard qw( Int );
my $tiny_type = Int;
my $moose_type = $tiny_type->moose_type;
Internally, this is what the "-moose" flag makes imported functions do.
Install Now
PNG Icons
Emojis
