On Sun, Jul 17, 2005 at 18:23:02 +0000, Luke Palmer wrote: > > * Coercion of parameters and a class's willingness to coerce > > into something is a better metric of distance > > Well, if you think metrics at all are a good way to do dispatch.
Well, we do have a notion of "closeness" already - that's what MMD
is about - a more particular method is chosen over a less particular
one. chromatic's idea is simply to make the way you determine
particularity based on the class's desire to fulfill the class/role
(a coercion distance), not on it's type hierarchy>
> Well, I like your proposal. It's a very generics-oriented world view,
> which I hold very dear. However, you didn't actually solve anything.
Yes, I'm aiming to destroy ;-)
> What happened to our numeric == and string eq. Are you proposing that
> we toss out string eq and let MMD do the work?
Yep. =)
Come to think of it - I just needed to compare strings in perl 5 - i
normally either match or use hashes as dispatch tables, so
comparison doesn't happen often. I used '==' instead of 'eq'.
> If I recall correctly the reason for == and eq existing and being
> distinct is so that you don't have to do:
>
> [EMAIL PROTECTED]()+$expression] == +%another{long($hairy % expression())
> }
> ^..................................^
>
> You can't see what's going on according to that operator, because the
> eye scanning distance is too great. We still need to satisfy the
> scripters who like the distinction between numeric and string
> comparison. It's hard for me to argue for them, since I'm not one of
> them.
Well, in that case doing an explicit MMD selection of == is in order
- yet another reason for that feature.
> One more possibility is operator adverbs. We could assume that == is
> generic unless you give it a :num or :str adverb:
>
> $a == $b # generic
> $a == $b :num # numeric
> $a == $b :str # string
yuck yuck yuck yuck yuck.... Now the one true version of == will be
patched once a week to support new adverbs, and those patches will
be promptly rejected, and there will be chaos.
--
() Yuval Kogman <[EMAIL PROTECTED]> 0xEBD27418 perl hacker &
/\ kung foo master: /methinks long and hard, and runs away: neeyah!!!
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