2026-05-21 22:10 @216.73.216.105 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
NAME
Type::Tiny - tiny, yet Moo(se)-compatible type constraint
SYNOPSIS
use v5.12;
use strict;
use warnings;
package Horse {
use Moo;
use Types::Standard qw( Str Int Enum ArrayRef Object );
use Type::Params qw( compile );
use namespace::autoclean;
has name => (
is => 'ro',
isa => Str,
required => 1,
);
has gender => (
is => 'ro',
isa => Enum[qw( f m )],
);
has age => (
is => 'rw',
isa => Int->where( '$_ >= 0' ),
);
has children => (
is => 'ro',
isa => ArrayRef[Object],
default => sub { return [] },
);
sub add_child {
state $check = compile( Object, Object ); # method signature
my ($self, $child) = $check->(@_); # unpack @_
push @{ $self->children }, $child;
return $self;
}
}
package main;
my $boldruler = Horse->new(
name => "Bold Ruler",
gender => 'm',
age => 16,
);
my $secretariat = Horse->new(
name => "Secretariat",
gender => 'm',
age => 0,
);
$boldruler->add_child( $secretariat );
STATUS
This module is covered by the Type-Tiny stability policy.
DESCRIPTION
This documents the internals of the Type::Tiny class. Type::Tiny::Manual
is a better starting place if you're new.
Type::Tiny is a small class for creating Moose-like type constraint
objects which are compatible with Moo, Moose and Mouse.
use Scalar::Util qw(looks_like_number);
use Type::Tiny;
my $NUM = "Type::Tiny"->new(
name => "Number",
constraint => sub { looks_like_number($_) },
message => sub { "$_ ain't a number" },
);
package Ermintrude {
use Moo;
has favourite_number => (is => "ro", isa => $NUM);
}
package Bullwinkle {
use Moose;
has favourite_number => (is => "ro", isa => $NUM);
}
package Maisy {
use Mouse;
has favourite_number => (is => "ro", isa => $NUM);
}
Maybe now we won't need to have separate MooseX, MouseX and MooX
versions of everything? We can but hope...
Constructor
"new(%attributes)"
Moose-style constructor function.
Attributes
Attributes are named values that may be passed to the constructor. For
each attribute, there is a corresponding reader method. For example:
my $type = Type::Tiny->new( name => "Foo" );
print $type->name, "\n"; # says "Foo"
Important attributes
These are the attributes you are likely to be most interested in
providing when creating your own type constraints, and most interested
in reading when dealing with type constraint objects.
"constraint"
Coderef to validate a value ($_) against the type constraint. The
coderef will not be called unless the value is known to pass any
parent type constraint (see "parent" below).
Alternatively, a string of Perl code checking $_ can be passed as a
parameter to the constructor, and will be converted to a coderef.
Defaults to "sub { 1 }" - i.e. a coderef that passes all values.
"parent"
Optional attribute; parent type constraint. For example, an
"Integer" type constraint might have a parent "Number".
If provided, must be a Type::Tiny object.
"inlined"
A coderef which returns a string of Perl code suitable for inlining
this type. Optional.
(The coderef will be called in list context and can actually return
a list of strings which will be joined with "&&". If the first item
on the list is undef, it will be substituted with the type's
parent's inline check.)
If "constraint" (above) is a coderef generated via Sub::Quote, then
Type::Tiny *may* be able to automatically generate "inlined" for
you. If "constraint" (above) is a string, it will be able to.
"name"
The name of the type constraint. These need to conform to certain
naming rules (they must begin with an uppercase letter and continue
using only letters, digits 0-9 and underscores).
Optional; if not supplied will be an anonymous type constraint.
"display_name"
A name to display for the type constraint when stringified. These
don't have to conform to any naming rules. Optional; a default name
will be calculated from the "name".
"library"
The package name of the type library this type is associated with.
Optional. Informational only: setting this attribute does not
install the type into the package.
"deprecated"
Optional boolean indicating whether a type constraint is deprecated.
Type::Library will issue a warning if you attempt to import a
deprecated type constraint, but otherwise the type will continue to
function as normal. There will not be deprecation warnings every
time you validate a value, for instance. If omitted, defaults to the
parent's deprecation status (or false if there's no parent).
"message"
Coderef that returns an error message when $_ does not validate
against the type constraint. Optional (there's a vaguely sensible
default.)
"coercion"
A Type::Coercion object associated with this type.
Generally speaking this attribute should not be passed to the
constructor; you should rely on the default lazily-built coercion
object.
You may pass "coercion => 1" to the constructor to inherit coercions
from the constraint's parent. (This requires the parent constraint
to have a coercion.)
"sorter"
A coderef which can be passed two values conforming to this type
constraint and returns -1, 0, or 1 to put them in order.
Alternatively an arrayref containing a pair of coderefs — a sorter
and a pre-processor for the Schwarzian transform. Optional.
The idea is to allow for:
@sorted = Int->sort( 2, 1, 11 ); # => 1, 2, 11
@sorted = Str->sort( 2, 1, 11 ); # => 1, 11, 2
"my_methods"
Experimental hashref of additional methods that can be called on the
type constraint object.
Attributes related to parameterizable and parameterized types
The following additional attributes are used for parameterizable (e.g.
"ArrayRef") and parameterized (e.g. "ArrayRef[Int]") type constraints.
Unlike Moose, these aren't handled by separate subclasses.
"constraint_generator"
Coderef that is called when a type constraint is parameterized. When
called, it is passed the list of parameters, though any parameter
which looks like a foreign type constraint (Moose type constraints,
Mouse type constraints, etc, *and coderefs(!!!)*) is first coerced
to a native Type::Tiny object.
Note that for compatibility with the Moose API, the base type is
*not* passed to the constraint generator, but can be found in the
package variable $Type::Tiny::parameterize_type. The first parameter
is also available as $_.
Types *can* be parameterized with an empty parameter list. For
example, in Types::Standard, "Tuple" is just an alias for "ArrayRef"
but "Tuple[]" will only allow zero-length arrayrefs to pass the
constraint. If you wish "YourType" and "YourType[]" to mean the same
thing, then do:
return $Type::Tiny::parameterize_type unless @_;
The constraint generator should generate and return a new constraint
coderef based on the parameters. Alternatively, the constraint
generator can return a fully-formed Type::Tiny object, in which case
the "name_generator", "inline_generator", and "coercion_generator"
attributes documented below are ignored.
Optional; providing a generator makes this type into a
parameterizable type constraint. If there is no generator,
attempting to parameterize the type constraint will throw an
exception.
"name_generator"
A coderef which generates a new display_name based on parameters.
Called with the same parameters and package variables as the
"constraint_generator". Expected to return a string.
Optional; the default is reasonable.
"inline_generator"
A coderef which generates a new inlining coderef based on
parameters. Called with the same parameters and package variables as
the "constraint_generator". Expected to return a coderef.
Optional.
"coercion_generator"
A coderef which generates a new Type::Coercion object based on
parameters. Called with the same parameters and package variables as
the "constraint_generator". Expected to return a blessed object.
Optional.
"deep_explanation"
This API is not finalized. Coderef used by
Error::TypeTiny::Assertion to peek inside parameterized types and
figure out why a value doesn't pass the constraint.
"parameters"
In parameterized types, returns an arrayref of the parameters.
Lazy generated attributes
The following attributes should not be usually passed to the
constructor; unless you're doing something especially unusual, you
should rely on the default lazily-built return values.
"compiled_check"
Coderef to validate a value ($_[0]) against the type constraint.
This coderef is expected to also handle all validation for the
parent type constraints.
"complementary_type"
A complementary type for this type. For example, the complementary
type for an integer type would be all things that are not integers,
including floating point numbers, but also alphabetic strings,
arrayrefs, filehandles, etc.
"moose_type", "mouse_type"
Objects equivalent to this type constraint, but as a
Moose::Meta::TypeConstraint or Mouse::Meta::TypeConstraint.
It should rarely be necessary to obtain a
Moose::Meta::TypeConstraint object from Type::Tiny because the
Type::Tiny object itself should be usable pretty much anywhere a
Moose::Meta::TypeConstraint is expected.
Methods
Predicate methods
These methods return booleans indicating information about the type
constraint. They are each tightly associated with a particular
attribute. (See "Attributes".)
"has_parent", "has_library", "has_inlined", "has_constraint_generator",
"has_inline_generator", "has_coercion_generator", "has_parameters",
"has_message", "has_deep_explanation", "has_sorter"
Simple Moose-style predicate methods indicating the presence or
absence of an attribute.
"has_coercion"
Predicate method with a little extra DWIM. Returns false if the
coercion is a no-op.
"is_anon"
Returns true iff the type constraint does not have a "name".
"is_parameterized", "is_parameterizable"
Indicates whether a type has been parameterized (e.g.
"ArrayRef[Int]") or could potentially be (e.g. "ArrayRef").
"has_parameterized_from"
Useless alias for "is_parameterized".
Validation and coercion
The following methods are used for coercing and validating values
against a type constraint:
"check($value)"
Returns true iff the value passes the type constraint.
"validate($value)"
Returns the error message for the value; returns an explicit undef
if the value passes the type constraint.
"assert_valid($value)"
Like "check($value)" but dies if the value does not pass the type
constraint.
Yes, that's three very similar methods. Blame
Moose::Meta::TypeConstraint whose API I'm attempting to emulate. :-)
"assert_return($value)"
Like "assert_valid($value)" but returns the value if it passes the
type constraint.
This seems a more useful behaviour than "assert_valid($value)". I
would have just changed "assert_valid($value)" to do this, except
that there are edge cases where it could break Moose compatibility.
"get_message($value)"
Returns the error message for the value; even if the value passes
the type constraint.
"validate_explain($value, $varname)"
Like "validate" but instead of a string error message, returns an
arrayref of strings explaining the reasoning why the value does not
meet the type constraint, examining parent types, etc.
The $varname is an optional string like '$foo' indicating the name
of the variable being checked.
"coerce($value)"
Attempt to coerce $value to this type.
"assert_coerce($value)"
Attempt to coerce $value to this type. Throws an exception if this
is not possible.
Child type constraint creation and parameterization
These methods generate new type constraint objects that inherit from the
constraint they are called upon:
"create_child_type(%attributes)"
Construct a new Type::Tiny object with this object as its parent.
"where($coderef)"
Shortcut for creating an anonymous child type constraint. Use it
like "HashRef->where(sub { exists($_->{name}) })". That said, you
can get a similar result using overloaded "&":
HashRef & sub { exists($_->{name}) }
Like the "constraint" attribute, this will accept a string of Perl
code:
HashRef->where('exists($_->{name})')
"child_type_class"
The class that create_child_type will construct by default.
"parameterize(@parameters)"
Creates a new parameterized type; throws an exception if called on a
non-parameterizable type.
"of(@parameters)"
A cute alias for "parameterize". Use it like "ArrayRef->of(Int)".
"plus_coercions($type1, $code1, ...)"
Shorthand for creating a new child type constraint with the same
coercions as this one, but then adding some extra coercions (at a
higher priority than the existing ones).
"plus_fallback_coercions($type1, $code1, ...)"
Like "plus_coercions", but added at a lower priority.
"minus_coercions($type1, ...)"
Shorthand for creating a new child type constraint with fewer type
coercions.
"no_coercions"
Shorthand for creating a new child type constraint with no coercions
at all.
Type relationship introspection methods
These methods allow you to determine a type constraint's relationship to
other type constraints in an organised hierarchy:
"equals($other)", "is_subtype_of($other)", "is_supertype_of($other)",
"is_a_type_of($other)"
Compare two types. See Moose::Meta::TypeConstraint for what these
all mean. (OK, Moose doesn't define "is_supertype_of", but you get
the idea, right?)
Note that these have a slightly DWIM side to them. If you create two
Type::Tiny::Class objects which test the same class, they're
considered equal. And:
my $subtype_of_Num = Types::Standard::Num->create_child_type;
my $subtype_of_Int = Types::Standard::Int->create_child_type;
$subtype_of_Int->is_subtype_of( $subtype_of_Num ); # true
"strictly_equals($other)", "is_strictly_subtype_of($other)",
"is_strictly_supertype_of($other)", "is_strictly_a_type_of($other)"
Stricter versions of the type comparison functions. These only care
about explicit inheritance via "parent".
my $subtype_of_Num = Types::Standard::Num->create_child_type;
my $subtype_of_Int = Types::Standard::Int->create_child_type;
$subtype_of_Int->is_strictly_subtype_of( $subtype_of_Num ); # false
"parents"
Returns a list of all this type constraint's ancestor constraints.
For example, if called on the "Str" type constraint would return the
list "(Value, Defined, Item, Any)".
*Due to a historical misunderstanding, this differs from the Moose
implementation of the "parents" method. In Moose, "parents" only
returns the immediate parent type constraints, and because type
constraints only have one immediate parent, this is effectively an
alias for "parent". The extension module
MooseX::Meta::TypeConstraint::Intersection is the only place where
multiple type constraints are returned; and they are returned as an
arrayref in violation of the base class' documentation. I'm keeping
my behaviour as it seems more useful.*
"find_parent($coderef)"
Loops through the parent type constraints *including the invocant
itself* and returns the nearest ancestor type constraint where the
coderef evaluates to true. Within the coderef the ancestor currently
being checked is $_. Returns undef if there is no match.
In list context also returns the number of type constraints which
had been looped through before the matching constraint was found.
"find_constraining_type"
Finds the nearest ancestor type constraint (including the type
itself) which has a "constraint" coderef.
Equivalent to:
$type->find_parent(sub { not $_->_is_null_constraint })
"coercibles"
Return a type constraint which is the union of type constraints that
can be coerced to this one (including this one). If this type
constraint has no coercions, returns itself.
"type_parameter"
In parameterized type constraints, returns the first item on the
list of parameters; otherwise returns undef. For example:
( ArrayRef[Int] )->type_parameter; # returns Int
( ArrayRef[Int] )->parent; # returns ArrayRef
Note that parameterizable type constraints can perfectly
legitimately take multiple parameters (several of the
parameterizable type constraints in Types::Standard do). This method
only returns the first such parameter. "Attributes related to
parameterizable and parameterized types" documents the "parameters"
attribute, which returns an arrayref of all the parameters.
"parameterized_from"
Harder to spell alias for "parent" that only works for parameterized
types.
*Hint for people subclassing Type::Tiny:* Since version 1.006000, the
methods for determining subtype, supertype, and type equality should
*not* be overridden in subclasses of Type::Tiny. This is because of the
problem of diamond inheritance. If X and Y are both subclasses of
Type::Tiny, they *both* need to be consulted to figure out how type
constraints are related; not just one of them should be overriding these
methods. See the source code for Type::Tiny::Enum for an example of how
subclasses can give hints about type relationships to Type::Tiny.
Summary: push a coderef onto @Type::Tiny::CMP. This coderef will be
passed two type constraints. It should then return one of the constants
Type::Tiny::CMP_SUBTYPE (first type is a subtype of second type),
Type::Tiny::CMP_SUPERTYPE (second type is a subtype of first type),
Type::Tiny::CMP_EQUAL (the two types are exactly the same),
Type::Tiny::CMP_EQUIVALENT (the two types are effectively the same), or
Type::Tiny::CMP_UNKNOWN (your coderef couldn't establish any
relationship).
Type relationship introspection function
"Type::Tiny::cmp($type1, $type2)"
The subtype/supertype relationship between types results in a
partial ordering of type constraints.
This function will return one of the constants:
Type::Tiny::CMP_SUBTYPE (first type is a subtype of second type),
Type::Tiny::CMP_SUPERTYPE (second type is a subtype of first type),
Type::Tiny::CMP_EQUAL (the two types are exactly the same),
Type::Tiny::CMP_EQUIVALENT (the two types are effectively the same),
or Type::Tiny::CMP_UNKNOWN (couldn't establish any relationship). In
numeric contexts, these evaluate to -1, 1, 0, 0, and 0, making it
potentially usable with "sort" (though you may need to silence
warnings about treating the empty string as a numeric value).
List processing methods
"grep(@list)"
Filters a list to return just the items that pass the type check.
@integers = Int->grep(@list);
"first(@list)"
Filters the list to return the first item on the list that passes
the type check, or undef if none do.
$first_lady = Woman->first(@people);
"map(@list)"
Coerces a list of items. Only works on types which have a coercion.
@truths = Bool->map(@list);
"sort(@list)"
Sorts a list of items according to the type's preferred sorting
mechanism, or if the type doesn't have a sorter coderef, uses the
parent type. If no ancestor type constraint has a sorter, throws an
exception. The "Str", "StrictNum", "LaxNum", and "Enum" type
constraints include sorters.
@sorted_numbers = Num->sort( Num->grep(@list) );
"rsort(@list)"
Like "sort" but backwards.
"any(@list)"
Returns true if any of the list match the type.
if ( Int->any(@numbers) ) {
say "there was at least one integer";
}
"all(@list)"
Returns true if all of the list match the type.
if ( Int->all(@numbers) ) {
say "they were all integers";
}
"assert_any(@list)"
Like "any" but instead of returning a boolean, returns the entire
original list if any item on it matches the type, and dies if none
does.
"assert_all(@list)"
Like "all" but instead of returning a boolean, returns the original
list if all items on it match the type, but dies as soon as it finds
one that does not.
Inlining methods
The following methods are used to generate strings of Perl code which
may be pasted into stringy "eval"uated subs to perform type checks:
"can_be_inlined"
Returns boolean indicating if this type can be inlined.
"inline_check($varname)"
Creates a type constraint check for a particular variable as a
string of Perl code. For example:
print( Types::Standard::Num->inline_check('$foo') );
prints the following output:
(!ref($foo) && Scalar::Util::looks_like_number($foo))
For Moose-compat, there is an alias "_inline_check" for this method.
"inline_assert($varname)"
Much like "inline_check" but outputs a statement of the form:
... or die ...;
Can also be called line "inline_assert($varname, $typevarname,
%extras)". In this case, it will generate a string of code that may
include $typevarname which is supposed to be the name of a variable
holding the type itself. (This is kinda complicated, but it allows a
useful string to still be produced if the type is not inlineable.)
The %extras are additional options to be passed to
Error::TypeTiny::Assertion's constructor and must be key-value pairs
of strings only, no references or undefs.
Other methods
"qualified_name"
For non-anonymous type constraints that have a library, returns a
qualified "MyLib::MyType" sort of name. Otherwise, returns the same
as "name".
"isa($class)", "can($method)", "AUTOLOAD(@args)"
If Moose is loaded, then the combination of these methods is used to
mock a Moose::Meta::TypeConstraint.
If Mouse is loaded, then "isa" mocks Mouse::Meta::TypeConstraint.
"DOES($role)"
Overridden to advertise support for various roles.
See also Type::API::Constraint, etc.
"TIESCALAR", "TIEARRAY", "TIEHASH"
These are provided as hooks that wrap Type::Tie. (Type::Tie is
distributed separately, and can be used with non-Type::Tiny type
constraints too.) They allow the following to work:
use Types::Standard qw(Int);
tie my @list, Int;
push @list, 123, 456; # ok
push @list, "Hello"; # dies
The following methods exist for Moose/Mouse compatibility, but do not do
anything useful.
"compile_type_constraint"
"hand_optimized_type_constraint"
"has_hand_optimized_type_constraint"
"inline_environment"
"meta"
Overloading
* Stringification is overloaded to return the qualified name.
* Boolification is overloaded to always return true.
* Coderefification is overloaded to call "assert_return".
* On Perl 5.10.1 and above, smart match is overloaded to call "check".
* The "==" operator is overloaded to call "equals".
* The "<" and ">" operators are overloaded to call "is_subtype_of" and
"is_supertype_of".
* The "~" operator is overloaded to call "complementary_type".
* The "|" operator is overloaded to build a union of two type
constraints. See Type::Tiny::Union.
* The "&" operator is overloaded to build the intersection of two type
constraints. See Type::Tiny::Intersection.
Previous versions of Type::Tiny would overload the "+" operator to call
"plus_coercions" or "plus_fallback_coercions" as appropriate. Support
for this was dropped after 0.040.
Constants
"Type::Tiny::SUPPORT_SMARTMATCH"
Indicates whether the smart match overload is supported on your
version of Perl.
Package Variables
$Type::Tiny::DD
This undef by default but may be set to a coderef that Type::Tiny
and related modules will use to dump data structures in things like
error messages.
Otherwise Type::Tiny uses it's own routine to dump data structures.
$DD may then be set to a number to limit the lengths of the dumps.
(Default limit is 72.)
This is a package variable (rather than get/set class methods) to
allow for easy localization.
$Type::Tiny::AvoidCallbacks
If this variable is set to true (you should usually do it in a
"local" scope), it acts as a hint for type constraints, when
generating inlined code, to avoid making any callbacks to variables
and functions defined outside the inlined code itself.
This should have the effect that "$type->inline_check('$foo')" will
return a string of code capable of checking the type on Perl
installations that don't have Type::Tiny installed. This is intended
to allow Type::Tiny to be used with things like Mite.
The variable works on the honour system. Types need to explicitly
check it and decide to generate different code based on its truth
value. The bundled types in Types::Standard, Types::Common::Numeric,
and Types::Common::String all do. (StrMatch is sometimes unable to,
and will issue a warning if it needs to rely on callbacks when asked
not to.)
Most normal users can ignore this.
Environment
"PERL_TYPE_TINY_XS"
Currently this has more effect on Types::Standard than Type::Tiny.
In future it may be used to trigger or suppress the loading XS
implementations of parts of Type::Tiny.
BUGS
Please report any bugs to
<https://github.com/tobyink/p5-type-tiny/issues>.
SEE ALSO
The Type::Tiny homepage <https://typetiny.toby.ink/>.
Type::Tiny::Manual, Type::API.
Type::Library, Type::Utils, Types::Standard, Type::Coercion.
Type::Tiny::Class, Type::Tiny::Role, Type::Tiny::Duck, Type::Tiny::Enum,
Type::Tiny::Union, Type::Tiny::Intersection.
Moose::Meta::TypeConstraint, Mouse::Meta::TypeConstraint.
Type::Params.
Type::Tiny on GitHub <https://github.com/tobyink/p5-type-tiny>,
Type::Tiny on Travis-CI <https://travis-ci.com/tobyink/p5-type-tiny>,
Type::Tiny on AppVeyor
<https://ci.appveyor.com/project/tobyink/p5-type-tiny>, Type::Tiny on
Codecov <https://codecov.io/gh/tobyink/p5-type-tiny>, Type::Tiny on
Coveralls <https://coveralls.io/github/tobyink/p5-type-tiny>.
AUTHOR
Toby Inkster <tobyink AT cpan.org>.
THANKS
Thanks to Matt S Trout for advice on Moo integration.
COPYRIGHT AND LICENCE
This software is copyright (c) 2013-2014, 2017-2021 by Toby Inkster.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
DISCLAIMER OF WARRANTIES
THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
Generated by phpMan Author: Che Dong On Apache Under GNU General Public License - MarkDown Format
2026-05-21 22:10 @216.73.216.105 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)