SPUG: Class::Multimethod Question

[Matt Tucker]

-- Asim Jalis <ajalis at cobaltgroup.com> spake thusly:

>> But in this case, as your examples show, there is enough information
>> when calling your constructor to distinguish between ObjectA and
>> ObjectB without using multimethods.  The multimethod technique would
>> make more sense if you were passing additional parameters to the
>> constructor, and wanted to choose ObjectA or ObjectB based on the
>> types of those parameters.
>
> The multimethods technique can potentially be quite useful with
> constructors.  It is common to provide one constructor which takes
> no parameters and then provide other constructors which over-ride the
> defaults.

A current possible workaround is:

package Foo;
sub new {
	my $class = shift;
	my $self = bless {}, $class;
	$self->init(@_);
	return $self;
}

multimethod init => (Foo) => sub {
	...
}

multimethod init => (Foo HASH) => sub {
	...
}
...etc.

However, it would be nice to have Multimethods actually do the right 
thing for new without requiring this workaround.

- Matt


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