Bug #73667 for MooseX-Types: Overload smart match

Mon Jan 02 03:00:28 2012 perl [...] toby.ink - Ticket created

Subject:

Overload smart match

package MooseX::Types::TypeDecorator; use overload '~~' => sub { my ($self, $val) = @_; $self->__type_constraint->check($val); }; This allows: if ($value ~~ PositiveInt) { print "It's a positive int\n"; } And even: given ($value) { when (PositiveInt) { print "It's a positive int\n"; } when (NegativeInt) { print "It's a negative int\n"; } }

Mon Jan 02 04:35:45 2012 perl [...] toby.ink - Correspondence added

As further info, this suggestion is inspired by Perl 6 that allows you to smart match against bareword type names. e.g. this Perl 5: if (ref $foo eq 'ARRAY') { say "foo is an array" } becomes this in Perl 6: if $foo ~~ Array { say "foo is an array" }

Mon Jan 02 04:35:46 2012 perl [...] toby.ink - Status changed from 'new' to 'open'

Mon Jan 23 14:40:26 2012 DROLSKY [...] cpan.org - Correspondence added

On Mon Jan 02 04:35:45 2012, TOBYINK wrote: Show quoted text

> As further info, this suggestion is inspired by Perl 6 that allows you > to smart match against bareword type names. > > e.g. this Perl 5: > > if (ref $foo eq 'ARRAY') { > say "foo is an array" > } > > becomes this in Perl 6: > > if $foo ~~ Array { > say "foo is an array" > } >

I think it'd make sense to hold off and see how smart match changes in future Perls. The current implementation may be deprecated and replaced with something simpler.

Fri Feb 03 11:15:44 2012 perl [...] toby.ink - Correspondence added

On 2012-01-23T19:40:26Z, DROLSKY wrote: Show quoted text

> I think it'd make sense to hold off and see how smart match changes

in Show quoted text

> future Perls. The current implementation may be deprecated and

replaced Show quoted text

> with something simpler.

As I understand it, the plan is to possibly change the implementation in favour of DOY's smartmatch::engine stuff which allows pluggable smartmatch engines, with at least two engines bundled with Perl: a backward compatible one, plus a simplified one used by default for "use 5.16" and above. Having looked at the code for both of these engines, the overloading I suggest would work under both of them. http://cpansearch.perl.org/src/DOY/smartmatch-engine-core-0.02-TRIAL/ lib/smartmatch/engine/core.pm https://github.com/doy/smartmatch-engine-rjbs/blob/master/lib/ smartmatch/engine/rjbs.pm

Mon May 21 08:59:51 2012 rjbs [...] cpan.org - Correspondence added

There are a few likely futures for ~~. These are presented in no particular order: 1. nothing changes, and we beg people not to use it 2. it is formally deprecated, to be removed at some point 3. it is given a second, simpler, better set of behaviors In (1) and (3), the meaning is going to remain, abstractly, $value ~~ $test In (2) it will, also, until it is fired into the sun, discussed thenceforth only in hushed tones. The same things go for given/when. I think the only thing making $value~~$moosetype a questionable idea is that it might encourage people to start using the badly-behaving things related to it: given (with its lexical topic) and the worser test types. This might be sufficiently addressed by a sentence of warning. Apart from that, Moose types are exactly the kind of thing that should overload ~~.

Mon Oct 15 18:26:18 2012 perl [...] toby.ink - Correspondence added

Looks like nuffin already got this working in a branch years ago; it's just not been merged into master... http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=gitmo/MooseX- Types.git;a=shortlog;h=refs/heads/topic/smartmatch