TypeConstraint[@TypeParameters or %TypeParameters]
-Where 'TypeParameters' is an array or hash of L<Moose::Meta::TypeConstraint>.
+Where 'TypeParameters' is an array reference or hash references of
+L<Moose::Meta::TypeConstraint> objects.
This type library enables structured type constraints. It is built on top of the
L<MooseX::Types> library system, so you should review the documentation for that
subtype ArrayOfInts,
as Arrayref[Int];
-which would constraint a value to something like [1,2,3,...] and so on. On the
+which would constrain a value to something like [1,2,3,...] and so on. On the
other hand, a structured type constraint explicitly names all it's allowed
'internal' type parameter constraints. For the example:
subtype StringFollowedByInt,
as Tuple[Str,Int];
-would constrain it's value to something like ['hello', 111] but ['hello', 'world']
+would constrain it's value to things like ['hello', 111] but ['hello', 'world']
would fail, as well as ['hello', 111, 'world'] and so on. Here's another
example:
Notice that the last type constraint in the structure is optional. This is
enabled via the helper Optional type constraint, which is a variation of the
core Moose type constraint 'Maybe'. The main difference is that Optional type
-constraints are required to validate if they exist, while Maybe permits undefined
-values. So the following example would not validate:
+constraints are required to validate if they exist, while 'Maybe' permits
+undefined values. So the following example would not validate:
StringIntOptionalHashRef->validate(['Hello Undefined', 1000, undef]);
allow both null and undefined, you should use the core Moose 'Maybe' type
constraint instead:
- use MooseX::Types -declare [qw(StringIntOptionalHashRef)];
+ use MooseX::Types -declare [qw(StringIntMaybeHashRef)];
use MooseX::Types::Moose qw(Maybe);
use MooseX::Types::Structured qw(Tuple);
- subtype StringIntOptionalHashRef,
+ subtype StringIntMaybeHashRef,
as Tuple[
Str, Int, Maybe[HashRef]
];
['World', 200, undef];
['World', 200];
-Structured Constraints are not limited to arrays. You can define a structure
-against a hashref with 'Dict' as in this example:
+Structured constraints are not limited to arrays. You can define a structure
+against a HashRef with 'Dict' as in this example:
subtype FirstNameLastName,
as Dict[
These structures can be as simple or elaborate as you wish. You can even
combine various structured, parameterized and simple constraints all together:
- subtype crazy,
+ subtype Crazy,
as Tuple[
Int,
Dict[name=>Str, age=>Int],
my $instance = MyApp::MyClass->new(
person=>MyApp::MyStruct->new(
full_name => 'John',
- age_in_years => 39
+ age_in_years => 39,
),
);
extending coercions to support this welcome on the Moose development channel or
mailing list.
+=head2 Recursion
+
+Newer versions of L<MooseX::Types> support recursive type constraints. That is
+you can include a type constraint as a contained type constraint of itself. For
+example:
+
+ subtype Person,
+ as Dict[
+ name=>Str,
+ friends=>Optional[
+ ArrayRef[Person]
+ ],
+ ];
+
+This would declare a Person subtype that contains a name and an optional
+ArrayRef of Persons who are friends as in:
+
+ {
+ name => 'Mike',
+ friends => [
+ { name => 'John' },
+ { name => 'Vincent' },
+ {
+ name => 'Tracey',
+ friends => [
+ { name => 'Stephenie' },
+ { name => 'Ilya' },
+ ],
+ },
+ ],
+ };
+
+Please take care to make sure the recursion node is either Optional, or declare
+a Union with an non recursive option such as:
+
+ subtype Value
+ as Tuple[
+ Str,
+ Str|Tuple,
+ ];
+
+Which validates:
+
+ [
+ 'Hello', [
+ 'World', [
+ 'Is', [
+ 'Getting',
+ 'Old',
+ ],
+ ],
+ ],
+ ];
+
+Otherwise you will define a subtype thatis impossible to validate since it is
+infinitely recursive. For more information about defining recursive types,
+please see the documentation in L<MooseX::Types> and the test cases.
+
=head1 TYPE CONSTRAINTS
This type library defines the following constraints.
list of contained constraints. For example:
Tuple[Int,Str]; ## Validates [1,'hello']
- Tuple[Str|Object, Int]; ##Validates ['hello', 1] or [$object, 2]
+ Tuple[Str|Object, Int]; ## Validates ['hello', 1] or [$object, 2]
=head2 Dict[%constraints]
use MooseX::Types -declare => [qw(Name Age Person)];
subtype Person,
- as Dict[name=>Str, age=>Int];
+ as Dict[
+ name=>Str,
+ age=>Int,
+ ];
coerce Person,
- from Dict[first=>Str, last=>Str, years=>Int],
- via { +{
+ from Dict[
+ first=>Str,
+ last=>Str,
+ years=>Int,
+ ], via { +{
name => "$_->{first} $_->{last}",
- age=>$_->{years},
+ age => $_->{years},
}},
- from Dict[fullname=>Dict[last=>Str, first=>Str], dob=>DateTime],
+ from Dict[
+ fullname=>Dict[
+ last=>Str,
+ first=>Str,
+ ],
+ dob=>DateTime,
+ ],
## DateTime needs to be inside of single quotes here to disambiguate the
## class package from the DataTime type constraint imported via the
## line "use MooseX::Types::DateTime qw(DateTime);"
}
## Make sure there are no leftovers.
if(@values) {
+ warn "I failed since there were left over values";
return;
} elsif(@type_constraints) {
+ warn "I failed due to left over TC";
return;
} else {
return 1;
=head1 TODO
-Need to clarify deep coercions, need to clarify subtypes of subtypes. Would
-like more and better examples and probably some best practices guidence.
+Here's a list of stuff I would be happy to get volunteers helping with:
+
+All POD examples need test cases in t/documentation/*.t
+Want to break out the examples section to a separate cookbook style POD.
+Want more examples and best practice / usage guidance for authors
+Need to clarify deep coercions,
+Need to clarify subtypes of subtypes.
=head1 AUTHOR
projects / gitmo/MooseX-Types-Structured.git / commitdiff