Shlomi Fish <[email protected]> writes:
> On Tuesday 27 Apr 2010 15:51:07 Stevan Little wrote:
>> On Apr 27, 2010, at 3:36 AM, Shlomi Fish wrote:
>> >
>> > After merging XML-Grammar-Fiction and XML-Grammar-Screenplay, I have
>> > accumulated several questions about Moose, so I'd post each one in a
>> > separate post to keep each thread single-topic. (I hope it's OK.)
>> >
>> > The first one is how to implement a Class::Std/Perl 6-like walkmeth:
>> >
>> > * http://blog.gmane.org/gmane.comp.lang.perl.qotw.discuss/month=20070701
>> >
>> > * http://search.cpan.org/perldoc?Class::Std (search for CUMULATIVE).
>> >
> [SNIP]
>> > My question is: is there a better way to do it using Moose? (Or one of
>> > the MooseX modules?) Instead, should I implement my own private logic or
>> > create a new MooseX module?
>>
>> No, that is pretty much how you would do it. Take a look at
>> Moose::Object::BUILDALL, it does the same thing.
>
> OK, thanks. I might create a small MooseX::AccumArray distro out of it.
If you do get around to looking at this, I have a couple of times played with
the idea of either hacking on Class::MOP[1], or writing an extension, to do some
more of the method combination bits that CLOS used to do.
Specifically, I have run across the need for:
'and' and 'or' method combination[2], both with most-specific-first and
least-specific-first ordering — various validations like ACL-style
authorisation, and data validation, benefit from those.
The "accumulate to array" method combination you mention is also quite useful,
but a bit obvious right now.
CLOS also had min, max, and plus method combinations, for which I can see some
logic exposing in Moose also — and probably some of the "...write your own"
too.
Daniel
Footnotes:
[1] This embeds the "standard" method combination inside
Class::MOP::Method::Wrapped as a private method internally; it doesn't
look terribly hard to extend to either use external method combination
classes, or to support non-standard (eg: not before, after, around)
decorators ... which makes me think I have missed something in my
look-but-not-touch investigation so far.
[2] I suspect that Perl users would like a "and-true" and "and-defined"
variant of both of these, that short-circuit when the value is false and
undefined respectively, where CLOS users didn't.
--
✣ Daniel Pittman ✉ [email protected] ☎ +61 401 155 707
♽ made with 100 percent post-consumer electrons
