in reply to Re^4: Near-free function currying in Perl
in thread Near-free function currying in Perl

I like
sub foo : required($$$) { ... }

That allows more than just currying to use the attribute. Also, you can then do something like:

sub foo : required( address, city, state, zip ) { ... }

That way, you can do both parameter validation and named-parameter currying (as per Limbic~Region's comment below). Plus, you're specifying the API, which would allow for something like doxygen to document your API.

An even nicer thing would be to combine this idea of a required() attribute to methods, meaning that you could do something like:

package Foo; sub new : required( attr1, attr2 ) : optional( attr3 ) { ... }

This would behave like Class::MethodMaker and create the attr1(), attr2(), and attr3() mutators, plus require that the first two be passed in to the constructor.

It wouldn't be too hard to come up with a list of useful function/method attributes. Off the top of my head, I can see multiple uses for:

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