package MooseX::Types::Structured;
-use 5.8.8;
-use Moose;
+use 5.008;
use Moose::Util::TypeConstraints;
use MooseX::Meta::TypeConstraint::Structured;
-use MooseX::Types -declare => [qw(Dict Tuple)];
+use MooseX::Types -declare => [qw(Dict Tuple Optional)];
-our $VERSION = '0.03';
+our $VERSION = '0.06';
our $AUTHORITY = 'cpan:JJNAPIORK';
=head1 NAME
use Moose;
use MooseX::Types::Moose qw(Str Int);
- use MooseX::Types::Structured qw(Dict Tuple);
-
- has name => (isa=>Dict[first_name=>Str, last_name=>Str]);
+ use MooseX::Types::Structured qw(Dict Optional);
+
+ ## A name has a first and last part, but middle names are not required
+ has name => (
+ isa=>Dict[
+ first=>Str,
+ last=>Str,
+ middle=>Optional[Str],
+ ],
+ );
Then you can instantiate this class with something like:
- my $instance = MyApp::MyClass->new(
- name=>{first_name=>'John', last_name=>'Napiorkowski'},
- );
+ my $john = MyApp::MyClass->new(
+ name => {
+ first=>'John',
+ middle=>'James'
+ last=>'Napiorkowski',
+ },
+ );
+
+Or with:
-But all of these would cause an error:
+ my $vanessa = MyApp::MyClass->new(
+ name => {
+ first=>'Vanessa',
+ last=>'Li'
+ },
+ );
- my $instance = MyApp::MyClass->new(name=>'John');
- my $instance = MyApp::MyClass->new(name=>{first_name=>'John'});
- my $instance = MyApp::MyClass->new(name=>{first_name=>'John', age=>39});
+But all of these would cause a constraint error for the 'name' attribute:
+ MyApp::MyClass->new( name=>'John' );
+ MyApp::MyClass->new( name=>{first_name=>'John'} );
+ MyApp::MyClass->new( name=>{first_name=>'John', age=>39} );
+ MyApp::MyClass->new( name=>{first=>'Vanessa', middle=>[1,2], last=>'Li'} );
+
Please see the test cases for more examples.
=head1 DESCRIPTION
-A structured type constraint is a standard container L</Moose> type constraint,
+A structured type constraint is a standard container L<Moose> type constraint,
such as an arrayref or hashref, which has been enhanced to allow you to
explicitly name all the allow type constraints inside the structure. The
generalized form is:
- TypeConstraint[TypeParameters]
+ TypeConstraint[@TypeParameters|%TypeParameters]
-Where TypeParameters is a list of type constraints.
+Where 'TypeParameters' is an array or hash of L<Moose::Meta::TypeConstraint>.
-This type library enables structured type constraints. It is build on top of the
+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
if you are not familiar with it.
=head2 Comparing Parameterized types to Structured types
-Parameterized constraints are built into the core Moose types 'HashRef' and
-'ArrayRef'. Structured types have similar functionality, so their syntax is
-likewise similar. For example, you could define a parameterized constraint like:
+Parameterized constraints are built into core Moose and you are probably already
+familuar with the type constraints 'HashRef' and 'ArrayRef'. Structured types
+have similar functionality, so their syntax is likewise similar. For example,
+you could define a parameterized constraint like:
- subtype HashOfInts,
- as Hashref[Int];
+ subtype ArrayOfInts,
+ as Arrayref[Int];
which would constraint 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 type
-parameter constraints. For the example:
+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 fail, as well as ['hello', 111, 'world']
+would fail, as well as ['hello', 111, 'world'] and so on. Here's another
+example:
+
+ subtype StringIntOptionalHashRef,
+ as Tuple[
+ Str, Int,
+ Optional[HashRef]
+ ];
+
+This defines a type constraint that validates values like:
+
+ ['Hello', 100, {key1=>'value1', key2=>'value2'}];
+ ['World', 200];
+
+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:
+
+ StringIntOptionalHashRef->validate(['Hello Undefined', 1000, undef]);
+
+Please note the subtle difference between undefined and null. If you wish to
+allow both null and undefined, you should use the core Moose Maybe type constraint
+instead:
+
+ use MooseX::Types -declare [qw(StringIntOptionalHashRef)];
+ use MooseX::Types::Moose qw(Maybe);
+ use MooseX::Types::Structured qw(Tuple);
+
+ subtype StringIntOptionalHashRef,
+ as Tuple[
+ Str, Int, Maybe[HashRef]
+ ];
+
+This would validate the following:
+
+ ['Hello', 100, {key1=>'value1', key2=>'value2'}];
+ ['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:
+
+ subtype FirstNameLastName,
+ as Dict[firstname=>Str, lastname=>Str];
+
+This would constrain a hashref to something like:
+
+ {firstname=>'Vanessa', lastname=>'Li'};
+
+but all the following would fail validation:
+
+ {first=>'Vanessa', last=>'Li'};
+ {firstname=>'Vanessa', lastname=>'Li', middlename=>'NA'};
+ ['Vanessa', 'Li'];
These structures can be as simple or elaborate as you wish. You can even
combine various structured, parameterized and simple constraints all together:
package MyApp::MyStruct;
use Moose;
- has $_ for qw(name age);
+ has $_ for qw(full_name age_in_years);
package MyApp::MyClass;
use Moose;
has person => (isa=>'MyApp::MyStruct');
my $instance = MyApp::MyClass->new(
- person=>MyApp::MyStruct->new(name=>'John', age=>39),
+ person=>MyApp::MyStruct->new(full_name=>'John', age_in_years=>39),
);
This method may take some additional time to setup but will give you more
flexibility. However, structured constraints are highly compatible with this
method, granting some interesting possibilities for coercion. Try:
- subtype 'MyStruct',
+ use MyApp::MyStruct;
+ use MooseX::Types::DateTime qw(DateTime);
+ use MooseX::Types -declare [qw(MyStruct)];
+ use MooseX::Types::Moose qw(Str Int);
+ use MooseX::Types::Structured qw(Dict);
+
+ ## Use class_type to create an ISA type constraint if your object doesn't
+ ## inherit from Moose::Object.
+ class_type 'MyApp::MyStruct';
+
+ ## Just a shorter version really.
+ subtype MyStruct,
as 'MyApp::MyStruct';
- coerce 'MyStruct',
- from (Dict[name=>Str, age=>Int]),
- via { MyApp::MyStruct->new(%$_) },
- from (Dict[last_name=>Str, first_name=>Str, dob=>DateTime]),
- via {
- my $name = $_->{first_name} .' '. $_->{last_name};
+ ## Add the coercions.
+ coerce MyStruct,
+ from Dict[
+ full_name=>Str,
+ age_in_years=>Int
+ ], via {
+ MyApp::MyStruct->new(%$_);
+ },
+ from Dict[
+ lastname=>Str,
+ firstname=>Str,
+ dob=>DateTime
+ ], via {
+ my $name = $_->{firstname} .' '. $_->{lastname};
my $age = DateTime->now - $_->{dob};
- MyApp::MyStruct->new( name=>$name, age=>$age->years );
+ MyApp::MyStruct->new( full_name=>$name, age_in_years=>$age->years );
};
-
-=head2 Subtyping a structured subtype
+
+If you are not familiar with how coercions work, check out the L<Moose> cookbook
+entry L<Moose::Cookbook::Recipe5> for an explanation. The section L</Coercions>
+has additional examples and discussion.
+
+=head2 Subtyping a Structured type constraint
You need to exercise some care when you try to subtype a structured type
as in this example:
subtype Person,
- as Dict[name=>Str, age=>iIt];
+ as Dict[name=>Str, age=>Int];
subtype FriendlyPerson,
as Person[name=>Str, age=>Int, totalFriends=>Int];
This will actually work BUT you have to take care that the subtype has a
structure that does not contradict the structure of it's parent. For now the
above works, but I will clarify the syntax for this at a future point, so
-it's recommended to avoid (should not realy be needed so much anyway). For
+it's recommended to avoid (should not really be needed so much anyway). For
now this is supported in an EXPERIMENTAL way. Your thoughts, test cases and
patches are welcomed for discussion.
as Dict[first=>Str, last=>Str];
coerce Person,
+ ## Coerce an object of a particular class
from BlessedPersonObject,
via { +{name=>$_->name, age=>$_->age} },
+ ## Coerce from [$name, $age]
from ArrayRef,
via { +{name=>$_->[0], age=>$_->[1] },
+ ## Coerce from {fullname=>{first=>...,last=>...}, dob=>$DateTimeObject}
from Dict[fullname=>Fullname, dob=>DateTime],
via {
my $age = $_->dob - DateTime->now;
coercions, such as a coercion on 'Fullname' or on 'DateTime', that coercion
won't currently get activated.
-Please see the test '07-coerce.t' for a more detailed example.
+Please see the test '07-coerce.t' for a more detailed example. Discussion on
+extending coercions to support this welcome on the Moose development channel or
+mailing list.
=head1 TYPE CONSTRAINTS
Tuple[Int,Str]; ## Validates [1,'hello']
Tuple[Str|Object, Int]; ##Validates ['hello', 1] or [$object, 2]
-=head2 Dict [%constraints]
+=head2 Dict[%constraints]
This defines a hashref based constraint which allowed you to validate a specific
hashref. For example:
Dict[name=>Str, age=>Int]; ## Validates {name=>'John', age=>39}
+=head2 Optional[$constraint]
+
+This is primarily a helper constraint for Dict and Tuple type constraints. What
+this allows if for you to assert that a given type constraint is allowed to be
+null (but NOT undefined). If the value is null, then the type constraint passes
+but if the value is defined it must validate against the type constraint. This
+makes it easy to make a Dict where one or more of the keys doesn't have to exist
+or a tuple where some of the values are not required. For example:
+
+ subtype Name() => as Dict[
+ first=>Str,
+ last=>Str,
+ middle=>Optional[Str],
+ ];
+
+Creates a constraint that validates against a hashref with the keys 'first' and
+'last' being strings and required while an optional key 'middle' is must be a
+string if it appears but doesn't have to appear. So in this case both the
+following are valid:
+
+ {first=>'John', middle=>'James', last=>'Napiorkowski'}
+ {first=>'Vanessa', last=>'Li'}
+
=head1 EXAMPLES
Here are some additional example usage for structured types. All examples can
MooseX::Meta::TypeConstraint::Structured->new(
name => "MooseX::Types::Structured::Tuple" ,
parent => find_type_constraint('ArrayRef'),
- constraint_generator=> sub {
+ constraint_generator=> sub {
## Get the constraints and values to check
- my @type_constraints = @{shift @_};
- my @values = @{shift @_};
+ my ($type_constraints, $values) = @_;
+ my @type_constraints = defined $type_constraints ? @$type_constraints: ();
+ my @values = defined $values ? @$values: ();
## Perform the checking
while(@type_constraints) {
my $type_constraint = shift @type_constraints;
return;
}
} else {
- return;
+ unless($type_constraint->check()) {
+ return;
+ }
}
}
## Make sure there are no leftovers.
MooseX::Meta::TypeConstraint::Structured->new(
name => "MooseX::Types::Structured::Dict",
parent => find_type_constraint('HashRef'),
- constraint_generator=> sub {
+ constraint_generator=> sub {
## Get the constraints and values to check
- my %type_constraints = @{shift @_};
- my %values = %{shift @_};
+ my ($type_constraints, $values) = @_;
+ my %type_constraints = defined $type_constraints ? @$type_constraints: ();
+ my %values = defined $values ? %$values: ();
## Perform the checking
while(%type_constraints) {
my($key, $type_constraint) = each %type_constraints;
unless($type_constraint->check($value)) {
return;
}
- } else {
- return;
+ } else {
+ unless($type_constraint->check()) {
+ return;
+ }
}
}
## Make sure there are no leftovers.
- if(%values) {
+ if(%values) {
return;
} elsif(%type_constraints) {
return;
)
);
+OPTIONAL: {
+ my $Optional = Moose::Meta::TypeConstraint::Parameterizable->new(
+ name => 'MooseX::Types::Structured::Optional',
+ package_defined_in => __PACKAGE__,
+ parent => find_type_constraint('Item'),
+ constraint => sub { 1 },
+ constraint_generator => sub {
+ my ($type_parameter, @args) = @_;
+ my $check = $type_parameter->_compiled_type_constraint();
+ return sub {
+ my (@args) = @_;
+ if(exists($args[0])) {
+ ## If it exists, we need to validate it
+ $check->($args[0]);
+ } else {
+ ## But it's is okay if the value doesn't exists
+ return 1;
+ }
+ }
+ }
+ );
+
+ Moose::Util::TypeConstraints::register_type_constraint($Optional);
+ Moose::Util::TypeConstraints::add_parameterizable_type($Optional);
+}
+
+
=head1 SEE ALSO
The following modules or resources may be of interest.
-L<Moose>, L<MooseX::TypeLibrary>, L<Moose::Meta::TypeConstraint>,
+L<Moose>, L<MooseX::Types>, L<Moose::Meta::TypeConstraint>,
L<MooseX::Meta::TypeConstraint::Structured>
=head1 TODO
projects / gitmo/MooseX-Types-Structured.git / blobdiff