Hi,
I've come up with a utility class for Params::Validate that provides
some mechanism to setup inheritable parameter validation for subroutines.
My main problem was that using Params::Validate, a lot of the code out
in CPAN uses lexicals to store the validation specs, therefore making
subclassing hard:
package Parent;
use Params::Validate;
my %FooValidate = (...);
sub foo { validate(@_, \%FooValidate) }
package Child;
use base qw(Parent);
use Params::Validate;
sub foo { # overrides Parent
# the only way to re-use validation from parent class is to
# call $self->SUPER::foo(...)
}
What I wanted was some way to flexibly inherit/manage Params::Validate
specs, so I created this module, tentatively named
Params::Validate::Inheritable
package MyClass;
use Params::Validate::Inheritable;
__PACKAGE__->set_pv_spec(foo => { type => Params::Validate::HASHREF() });
sub foo
{
my $self = shift;
# validate @_ according to set_pv_spec() above
my %args = $self->validate_args([EMAIL PROTECTED]);
...
}
package MySubClass;
use base qw(MyClass);
__PACKAGE__->set_pv_spec(foo => \%newspec);
sub foo
{
my $self = shift;
# now validate @_ according to %newspec, not MyClass' spec for foo
my %args = $self->validate_args([EMAIL PROTECTED]);
# you can call the super class' method as well, and it will
# use the correct spec
$self->SUPER::validate_args(...);
}
The module is tentatively named Params::Validate::Inheritable, but Dave
Rolsky and I neither like that particular idea. To quote Dave:
I think P::V::Inheritable isn't quite right for classes that
are intended to be generic superclasses, or to add methods to
other classes.
In fact, it's really a role-type class, and something like
Class::Validating might be better.
On top of Dave's suggestion I'm thinking towards the line of
Class::ValidateArgs, Class::Validation, Class::ParamValidation, etc.
Please let me know if you have any comments.
regards,
--d
