1 package MooseX::TypeLibrary;
5 MooseX::TypeLibrary - Organise your Moose types in libraries
13 use Moose::Util::TypeConstraints;
14 use MooseX::TypeLibrary::Base ();
15 use MooseX::TypeLibrary::Util qw( filter_tags );
16 use MooseX::TypeLibrary::UndefinedType;
17 use Sub::Install qw( install_sub );
22 my $UndefMsg = q{Action for type '%s' not yet defined in library '%s'};
32 # predeclare our own types
33 use MooseX::TypeLibrary
34 -declare => [qw( PositiveInt NegativeInt )];
36 # import builtin types
37 use MooseX::TypeLibrary::Moose 'Int';
43 message { "Int is not larger than 0" };
48 message { "Int is not smaller than 0" };
62 use MyLibrary qw( PositiveInt NegativeInt );
64 # use the exported constants as type names
76 print "positive\n" if is_PositiveInt($value);
77 print "negative\n" if is_NegativeInt($value);
79 # coerce the value, NegativeInt doesn't have a coercion
80 # helper, since it didn't define any coercions.
81 $value = to_PositiveInt($value) or die "Cannot coerce";
88 The types provided with L<Moose> are by design global. This package helps
89 you to organise and selectively import your own and the built-in types in
90 libraries. As a nice side effect, it catches typos at compile-time too.
92 However, the main reason for this module is to provide an easy way to not
93 have conflicts with your type names, since the internal fully qualified
94 names of the types will be prefixed with the library's name.
96 This module will also provide you with some helper functions to make it
97 easier to use Moose types in your code.
99 =head1 TYPE HANDLER FUNCTIONS
103 A constant with the name of your type. It contains the type's fully
104 qualified name. Takes no value, as all constants.
108 This handler takes a value and tests if it is a valid value for this
109 C<$type>. It will return true or false.
113 A handler that will take a value and coerce it into the C<$type>. It will
114 return a false value if the type could not be coerced.
116 B<Important Note>: This handler will only be exported for types that can
117 do type coercion. This has the advantage that a coercion to a type that
118 cannot hasn't defined any coercions will lead to a compile-time error.
120 =head1 LIBRARY DEFINITION
122 A MooseX::TypeLibrary is just a normal Perl module. Unlike Moose
123 itself, it does not install C<use strict> and C<use warnings> in your
124 class by default, so this is up to you.
126 The only thing a library is required to do is
128 use MooseX::TypeLibrary -declare => \@types;
130 with C<@types> being a list of types you wish to define in this library.
131 This line will install a proper base class in your package as well as the
132 full set of L<handlers|/"TYPE HANDLER FUNCTIONS"> for your declared
133 types. It will then hand control over to L<Moose::Util::TypeConstraints>'
134 C<import> method to export the functions you will need to declare your
137 If you want to use Moose' built-in types (e.g. for subtyping) you will
140 use MooseX::TypeLibrary::Moose @types;
142 to import the helpers from the shipped L<MooseX::TypeLibrary::Moose>
143 library which can export all types that come with Moose.
145 You will have to define coercions for your types or your library won't
146 export a L</to_$type> coercion helper for it.
150 You can import the L<"type helpers"|/"TYPE HANDLER FUNCTIONS"> of a
151 library by C<use>ing it with a list of types to import as arguments. If
152 you want all of them, use the C<:all> tag. For example:
154 use MyLibrary ':all';
155 use MyOtherLibrary qw( TypeA TypeB );
157 MooseX::TypeLibrary comes with a library of Moose' built-in types called
158 L<MooseX::TypeLibrary::Moose>.
160 =head1 WRAPPING A LIBRARY
162 You can define your own wrapper subclasses to manipulate the behaviour
163 of a set of library exports. Here is an example:
168 use base 'MooseX::TypeLibrary::Wrapper';
170 sub coercion_export_generator {
172 my $code = $class->next::method(@_);
174 my $value = $code->(@_);
175 warn "Coercion returned undef!"
176 unless defined $value;
183 This class wraps the coercion generator (e.g., C<to_Int()>) and warns
184 if a coercion returned an undefined value. You can wrap any library
189 use MyWrapper MyLibrary => [qw( Foo Bar )],
190 Moose => [qw( Str Int )];
195 The C<Moose> library name is a special shortcut for
196 L<MooseX::TypeLibrary::Moose>.
198 =head2 Generator methods you can overload
202 =item type_export_generator( $short, $full )
204 Creates a closure returning the type's L<Moose::Meta::TypeConstraint>
207 =item check_export_generator( $short, $full, $undef_message )
209 This creates the closure used to test if a value is valid for this type.
211 =item coercion_export_generator( $short, $full, $undef_message )
213 This is the closure that's doing coercions.
217 =head2 Provided Parameters
223 The short, exported name of the type.
227 The fully qualified name of this type as L<Moose> knows it.
231 A message that will be thrown when type functionality is used but the
232 type does not yet exist.
240 Installs the L<MooseX::TypeLibrary::Base> class into the caller and
241 exports types according to the specification described in
242 L</"LIBRARY DEFINITION">. This will continue to
243 L<Moose::Util::TypeConstraints>' C<import> method to export helper
244 functions you will need to declare your types.
249 my ($class, %args) = @_;
252 # inject base class into new library
254 unshift @{ $callee . '::ISA' }, 'MooseX::TypeLibrary::Base';
257 # generate predeclared type helpers
258 if (my @orig_declare = @{ $args{ -declare } || [] }) {
259 my ($tags, $declare) = filter_tags @orig_declare;
261 for my $type (@$declare) {
262 $callee->add_type($type);
263 $callee->export_type_into(
265 sprintf($UndefMsg, $type, $callee),
271 # run type constraints import
272 return Moose::Util::TypeConstraints->import({ into => $callee });
275 =head2 type_export_generator
277 Generate a type export, e.g. C<Int()>. This will return either a
278 L<Moose::Meta::TypeConstraint> object, or alternatively a
279 L<MooseX::TypeLibrary::UndefinedType> object if the type was not
284 sub type_export_generator {
285 my ($class, $type, $full) = @_;
287 return find_type_constraint($full)
288 || MooseX::TypeLibrary::UndefinedType->new($full);
292 =head2 coercion_export_generator
294 This generates a coercion handler function, e.g. C<to_Int($value)>.
298 sub coercion_export_generator {
299 my ($class, $type, $full, $undef_msg) = @_;
303 # we need a type object
304 my $tobj = find_type_constraint($full) or croak $undef_msg;
305 my $return = $tobj->coerce($value);
307 # non-successful coercion returns false
308 return unless $tobj->check($return);
314 =head2 check_export_generator
316 Generates a constraint check closure, e.g. C<is_Int($value)>.
320 sub check_export_generator {
321 my ($class, $type, $full, $undef_msg) = @_;
325 # we need a type object
326 my $tobj = find_type_constraint($full) or croak $undef_msg;
328 return $tobj->check($value);
334 A library makes the types quasi-unique by prefixing their names with (by
335 default) the library package name. If you're only using the type handler
336 functions provided by MooseX::TypeLibrary, you shouldn't ever have to use
337 a type's actual full name.
341 L<Moose>, L<Moose::Util::TypeConstraints>, L<MooseX::TypeLibrary::Moose>
343 =head1 AUTHOR AND COPYRIGHT
345 Robert 'phaylon' Sedlacek C<E<lt>rs@474.atE<gt>>, with many thanks to
346 the C<#moose> cabal on C<irc.perl.org>.
350 This program is free software; you can redistribute it and/or modify
351 it under the same terms as perl itself.