chromatic <[EMAIL PROTECTED]> writes:
> On Tue, 2004-01-06 at 22:26, Austin Hastings wrote:
>
>> So on the grand balance of utility, what are the metrics that traits are
>> supposed to help improve?
>
> Two big ones:
>
> - naming collections of behavior that are too fine-grained to fit into
> classes cleanly
> - enabling finer-grained code reuse
>
> Consider a method that needs to print an object. You might require a
> String:
>
> sub print_it ( String $thingie )
> {
> print $thingie;
> }
>
> Why does it have to be a String, though? What prevents it from working
> with anything that can stringify, besides the overly restrictive
> signature? What if you could say (the Perl 6 equivalent of):
>
> sub print_it ( does Stringify $thingie )
> {
> print $thingie.stringify();
> }
>
> That's both more general and something more specific. By asking for
> what you really want, you're not coding everyone else into a corner.
In this particular case I prefer the Smalltalk thing of requiring all
objects to have a C<print_on($aStream)> method and not even requiring
that C<$aStream> satisfy the Stream role. But that's probably a matter
of taste.
--
Beware the Perl 6 early morning joggers -- Allison Randal
