Provided by: libspecio-perl_0.48-1_all 
NAME
Specio::Declare - Specio declaration subroutines
VERSION
version 0.48
SYNOPSIS
package MyApp::Type::Library;
use parent 'Specio::Exporter';
use Specio::Declare;
use Specio::Library::Builtins;
declare(
'Foo',
parent => t('Str'),
where => sub { $_[0] =~ /foo/i },
);
declare(
'ArrayRefOfInt',
parent => t( 'ArrayRef', of => t('Int') ),
);
my $even = anon(
parent => t('Int'),
inline => sub {
my $type = shift;
my $value_var = shift;
return $value_var . ' % 2 == 0';
},
);
coerce(
t('ArrayRef'),
from => t('Foo'),
using => sub { [ $_[0] ] },
);
coerce(
$even,
from => t('Int'),
using => sub { $_[0] % 2 ? $_[0] + 1 : $_[0] },
);
# Specio name is DateTime
any_isa_type('DateTime');
# Specio name is DateTimeObject
object_isa_type( 'DateTimeObject', class => 'DateTime' );
any_can_type(
'Duck',
methods => [ 'duck_walk', 'quack' ],
);
object_can_type(
'DuckObject',
methods => [ 'duck_walk', 'quack' ],
);
enum(
'Colors',
values => [qw( blue green red )],
);
intersection(
'HashRefAndArrayRef',
of => [ t('HashRef'), t('ArrayRef') ],
);
union(
'IntOrArrayRef',
of => [ t('Int'), t('ArrayRef') ],
);
DESCRIPTION
This package exports a set of type declaration helpers. Importing this package also causes
it to create a "t" subroutine in the calling package.
SUBROUTINES
This module exports the following subroutines.
t('name')
This subroutine lets you access any types you have declared so far, as well as any types
you imported from another type library.
If you pass an unknown name, it throws an exception.
declare(...)
This subroutine declares a named type. The first argument is the type name, followed by a
set of key/value parameters:
• parent => $type
The parent should be another type object. Specifically, it can be anything which does
the Specio::Constraint::Role::Interface role. The parent can be a named or anonymous
type.
• where => sub { ... }
This is a subroutine which defines the type constraint. It will be passed a single
argument, the value to check, and it should return true or false to indicate whether
or not the value is valid for the type.
This parameter is mutually exclusive with the "inline" parameter.
• inline => sub { ... }
This is a subroutine that is called to generate inline code to validate the type.
Inlining can be much faster than simply providing a subroutine with the "where"
parameter, but is often more complicated to get right.
The inline generator is called as a method on the type with one argument. This
argument is a string containing the variable name to use in the generated code.
Typically this is something like '$_[0]' or '$value'.
The inline generator subroutine should return a string of code representing a single
term, and it should not be terminated with a semicolon. This allows the inlined code
to be safely included in an "if" statement, for example. You can use "do { }" blocks
and ternaries to get everything into one term. Do not assign to the variable you are
testing. This single term should evaluate to true or false.
The inline generator is expected to include code to implement both the current type
and all its parents. Typically, the easiest way to do this is to write a subroutine
something like this:
sub {
my $self = shift;
my $var = shift;
return $self->parent->inline_check($var)
. ' and more checking code goes here';
}
Or, more concisely:
sub { $_[0]->parent->inline_check( $_[1] ) . 'more code that checks $_[1]' }
The "inline" parameter is mutually exclusive with the "where" parameter.
• message_generator => sub { ... }
A subroutine to generate an error message when the type check fails. The default
message says something like "Validation failed for type named Int declared in package
Specio::Library::Builtins (.../Specio/blib/lib/Specio/Library/Builtins.pm) at line 147
in sub named (eval) with value 1.1".
You can override this to provide something more specific about the way the type
failed.
The subroutine you provide will be called as a method on the type with two arguments.
The first is the description of the type (the bit in the message above that starts
with "type named Int ..." and ends with "... in sub named (eval)". This description
says what the thing is and where it was defined.
The second argument is the value that failed the type check, after any coercions that
might have been applied.
anon(...)
This subroutine declares an anonymous type. It is identical to "declare" except that it
expects a list of key/value parameters without a type name as the first parameter.
coerce(...)
This declares a coercion from one type to another. The first argument should be an object
which does the Specio::Constraint::Role::Interface role. This can be either a named or
anonymous type. This type is the type that the coercion is to.
The remaining arguments are key/value parameters:
• from => $type
This must be an object which does the Specio::Constraint::Role::Interface role. This
is type that we are coercing from. Again, this can be either a named or anonymous
type.
• using => sub { ... }
This is a subroutine which defines the type coercion. It will be passed a single
argument, the value to coerce. It should return a new value of the type this coercion
is to.
This parameter is mutually exclusive with the "inline" parameter.
• inline => sub { ... }
This is a subroutine that is called to generate inline code to perform the coercion.
The inline generator is called as a method on the type with one argument. This
argument is a string containing the variable name to use in the generated code.
Typically this is something like '$_[0]' or '$value'.
The inline generator subroutine should return a string of code representing a single
term, and it should not be terminated with a semicolon. This allows the inlined code
to be safely included in an "if" statement, for example. You can use "do { }" blocks
and ternaries to get everything into one term. This single term should evaluate to the
new value.
DECLARATION HELPERS
This module also exports some helper subs for declaring certain kinds of types:
any_isa_type, object_isa_type
The "any_isa_type" helper creates a type which accepts a class name or object of the given
class. The "object_isa_type" helper creates a type which only accepts an object of the
given class.
These subroutines take a type name as the first argument. The remaining arguments are
key/value pairs. Currently this is just the "class" key, which should be a class name.
This is the class that the type requires.
The type name argument can be omitted to create an anonymous type.
You can also pass just a single argument, in which case that will be used as both the
type's name and the class for the constraint to check.
any_does_type, object_does_type
The "any_does_type" helper creates a type which accepts a class name or object which does
the given role. The "object_does_type" helper creates a type which only accepts an object
which does the given role.
These subroutines take a type name as the first argument. The remaining arguments are
key/value pairs. Currently this is just the "role" key, which should be a role name. This
is the class that the type requires.
This should just work (I hope) with roles created by Moose, Mouse, and Moo (using
Role::Tiny).
The type name argument can be omitted to create an anonymous type.
You can also pass just a single argument, in which case that will be used as both the
type's name and the role for the constraint to check.
any_can_type, object_can_type
The "any_can_type" helper creates a type which accepts a class name or object with the
given methods. The "object_can_type" helper creates a type which only accepts an object
with the given methods.
These subroutines take a type name as the first argument. The remaining arguments are
key/value pairs. Currently this is just the "methods" key, which can be either a string or
array reference of strings. These strings are the required methods for the type.
The type name argument can be omitted to create an anonymous type.
enum
This creates a type which accepts a string matching a given list of acceptable values.
The first argument is the type name. The remaining arguments are key/value pairs.
Currently this is just the "values" key. This should an array reference of acceptable
string values.
The type name argument can be omitted to create an anonymous type.
intersection
This creates a type which is the intersection of two or more other types. A union only
accepts values which match all of its underlying types.
The first argument is the type name. The remaining arguments are key/value pairs.
Currently this is just the "of" key. This should an array reference of types.
The type name argument can be omitted to create an anonymous type.
union
This creates a type which is the union of two or more other types. A union accepts any of
its underlying types.
The first argument is the type name. The remaining arguments are key/value pairs.
Currently this is just the "of" key. This should an array reference of types.
The type name argument can be omitted to create an anonymous type.
PARAMETERIZED TYPES
You can create a parameterized type by calling "t" with additional parameters, like this:
my $arrayref_of_int = t( 'ArrayRef', of => t('Int') );
my $arrayref_of_hashref_of_int = t(
'ArrayRef',
of => t(
'HashRef',
of => t('Int'),
),
);
The "t" subroutine assumes that if it receives more than one argument, it should look up
the named type and call "$type->parameterize(...)" with the additional arguments.
If the named type cannot be parameterized, it throws an error.
You can also call "$type->parameterize" directly if needed. See
Specio::Constraint::Parameterizable for details.
SUPPORT
Bugs may be submitted at <https://github.com/houseabsolute/Specio/issues>.
SOURCE
The source code repository for Specio can be found at
<https://github.com/houseabsolute/Specio>.
AUTHOR
Dave Rolsky <autarch@urth.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2012 - 2022 by Dave Rolsky.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)
The full text of the license can be found in the LICENSE file included with this
distribution.