package MooseX::Types::Structured;
+use 5.008;
use Moose;
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 = '0.02';
+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'},
- );
-
-But all of these would cause an error:
+ my $john = MyApp::MyClass->new(
+ name => {
+ first=>'John',
+ middle=>'James'
+ last=>'Napiorkowski',
+ },
+ );
+
+ 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,
such as an arrayref or hashref, which has been enhanced to allow you to
-explicitely name all the allow type constraints inside the structure. The
+explicitly name all the allow type constraints inside the structure. The
generalized form is:
TypeConstraint[TypeParameters]
-Where TypeParameters is a list of type constraints.
+Where 'TypeParameters' is an array or hash of L</Moose::Meta::TypeConstraint>
+type constraints.
+
+This type library enables structured type constraints. It is build 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
-This type library enables structured type constraints. These work in a similar
-way to parameterized constraints that are built into the core Moose types,
-except that you are allowed to define the container's entire structure. For
-example, you could define a parameterized constraint like so:
+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:
- 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 constrain explicitly names all it's allowed type
+other hand, a structured type constraint explicitly names all it's allowed type
parameter constraints. For the example:
subtype StringFollowedByInt,
as Tuple[Str,Int];
-would constrain it's value to something like ['hello', 111];
+would constrain it's value to something like ['hello', 111] but ['hello', 'world']
+would fail, as well as ['hello', 111, 'world'] and so on.
+
+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[firste=>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:
];
Which would match "[1, {name=>'John', age=>25},[10,11,12]]". Please notice how
-the type parameters
+the type parameters can be visually arranged to your liking and to improve the
+clarity of your meaning. You don't need to run then altogether onto a single
+line.
+
+=head2 Alternatives
You should exercise some care as to whether or not your complex structured
constraints would be better off contained by a real object as in the following
coerce 'MyStruct',
from (Dict[name=>Str, age=>Int]),
- via {
- MyApp::MyStruct->new(%$_);
- },
+ via { MyApp::MyStruct->new(%$_) },
from (Dict[last_name=>Str, first_name=>Str, dob=>DateTime]),
via {
my $name = $_->{first_name} .' '. $_->{last_name};
my $age = DateTime->now - $_->{dob};
- MyApp::MyStruct->new(
- name=>$name,
- age=>$age->years );
+ MyApp::MyStruct->new( name=>$name, age=>$age->years );
};
=head2 Subtyping a structured subtype
as in this example:
subtype Person,
- as Dict[name=>Str, age=>iIt];
+ as Dict[name=>Str, age=>Int];
subtype FriendlyPerson,
as Person[name=>Str, age=>Int, totalFriends=>Int];
This will actually work BUT you have to take care that the subtype has a
structure that does not contradict the structure of it's parent. For now the
-above works, but I will probably clarify how this works at a future point, so
+above works, but I will clarify the syntax for this at a future point, so
it's recommended to avoid (should not realy be needed so much anyway). For
-now this is supported in an EXPERIMENTAL way. In the future we will probably
-clarify how to augment existing structured types.
+now this is supported in an EXPERIMENTAL way. Your thoughts, test cases and
+patches are welcomed for discussion.
=head2 Coercions
as Dict[first=>Str, last=>Str];
coerce Person,
+ ## Coerce an object of a particular class
from BlessedPersonObject,
via { +{name=>$_->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 = $_->dob - DateTime->now;
Dict[name=>Str, age=>Int]; ## Validates {name=>'John', age=>39}
+=head2 Optional [$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
+be found also in the 't/examples.t' test. Your contributions are also welcomed.
+
+=head2 Normalize a HashRef
+
+You need a hashref to conform to a canonical structure but are required accept a
+bunch of different incoming structures. You can normalize using the Dict type
+constraint and coercions. This example also shows structured types mixed which
+other MooseX::Types libraries.
+
+ package Test::MooseX::Meta::TypeConstraint::Structured::Examples::Normalize;
+
+ use Moose;
+ use DateTime;
+
+ use MooseX::Types::Structured qw(Dict Tuple);
+ use MooseX::Types::DateTime qw(DateTime);
+ use MooseX::Types::Moose qw(Int Str Object);
+ use MooseX::Types -declare => [qw(Name Age Person)];
+
+ subtype Person,
+ as Dict[name=>Str, age=>Int];
+
+ coerce Person,
+ from Dict[first=>Str, last=>Str, years=>Int],
+ via { +{
+ name => "$_->{first} $_->{last}",
+ age=>$_->{years},
+ }},
+ from Dict[fullname=>Dict[last=>Str, first=>Str], dob=>DateTime],
+ via { +{
+ name => "$_->{fullname}{first} $_->{fullname}{last}",
+ age => ($_->{dob} - 'DateTime'->now)->years,
+ }};
+
+ has person => (is=>'rw', isa=>Person, coerce=>1);
+
=cut
Moose::Util::TypeConstraints::get_type_constraint_registry->add_type_constraint(
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;
delete $values{$key};
unless($type_constraint->check($value)) {
return;
- #if ($type_constraint->has_coercion) {
- # my $temp = $type_constraint->coerce($value);
- # use Data::Dump qw/dump/; warn dump $value, $temp;
- # unless($type_constraint->check($temp)) {
- # return;
- # }
- #} else {
- # return;
- #}
}
- } else {
- return;
+ } else {
+ unless($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.
projects / gitmo/MooseX-Types-Structured.git / blobdiff