Type::Tiny::ConstrainedObject

Status

This module is considered experiemental.

Description

Methods

The following methods exist for Type::Tiny::Class, Type::Tiny::Role, Type::Tiny::Duck, and any type constraints that inherit from Object or Overload in Types::Standard.

These methods will also work for Type::Tiny::Intersection if at least one of the types in the intersection provides these methods.

These methods will also work for Type::Tiny::Union if all of the types in the union provide these methods.

stringifies_to($constraint)

Generates a new child type constraint which checks the object's stringification against a constraint. For example:

   my $type  = Type::Tiny::Class->new(class => 'URI');
   my $child = $type->stringifies_to( StrMatch[qr/^http:/] );
   
   $child->assert_valid( URI->new("http://example.com/") );

In the above example, $child is a type constraint that checks objects are blessed into (or inherit from) the URI class, and when stringified (e.g. though overloading) the result matches the regular expression qr/^http:/.

$constraint may be a type constraint, something that can be coerced to a type constraint (such as a coderef returning a boolean), a string of Perl code operating on $_, or a reference to a regular expression.

So the following would work:

   my $child = $type->stringifies_to( sub { qr/^http:/ } );
   my $child = $type->stringifies_to(       qr/^http:/   );
   my $child = $type->stringifies_to(       'm/^http:/'  );
   
   my $child = $type->where('"$_" =~ /^http:/');

numifies_to($constraint)

The same as stringifies_to but checks numification.

The following might be useful:

   use Types::Standard qw(Int Overload);
   my $IntLike = Int | Overload->numifies_to(Int)

with_attribute_values($attr1 => $constraint1, ...)

This is best explained with an example:

   use Types::Standard qw(InstanceOf StrMatch);
   use Types::Common::Numeric qw(IntRange);
   
   my $person = InstanceOf['Local::Human'];
   my $woman  = $person->with_attribute_values(
      gender   => StrMatch[ qr/^F/i  ],
      age      => IntRange[ 18 => () ],
   );
   
   $woman->assert_valid($alice);

This assertion will firstly check that $alice is a Local::Human, then check that $alice->gender starts with an "F", and lastly check that $alice->age is an integer at least 18.

Again, constraints can be type constraints, coderefs, strings of Perl code, or regular expressions.

Technically the "attributes" don't need to be Moo/Moose/Mouse attributes, but any methods which can be called with no parameters and return a scalar.

Bugs

Please report any bugs to https://github.com/tobyink/p5-type-tiny/issues.

See Also

Type::Tiny::Manual.

Type::Tiny.