Front page | perl.perl5.porters |
Postings from September 2015
* Aristotle Pagaltzis <pagaltzis@gmx.de> [2015-09-11T17:25:04]
> However, there is one case for it: if `when` is defined in terms of
> smartmatch, then these rules would allow writing e.g.
>
> given ($mode) {
> when ('enable') { ... }
> when ('disable') { ... }
> # ...
> }
I have a lot of sympathy for this position, and maybe I'd say I'm on the fence,
but I lean heavily to not doing it (yet) because I start to lose my mind when
these differ in behavior so radically:
my $x = 1;
... when 1;
... when $x;
I would be happy to be convinced, here, so have at me! Perhaps the real issue
is documenting this in a way that makes the above not surprising, even if you
only read the first few lines of the docs. I'm not sure.
* Aristotle Pagaltzis <pagaltzis@gmx.de> [2015-09-11T18:04:29]
> That said, I think this could be acceptable, but for one thing: that it
> uses the same overload method for $x ~~ $obj as for $obj ~~ $x.
Ugh, tell me about it. When I wrote the ~~ overloads, I was unhappy by the
crap needed. Maybe we should add ~~x and x~~. Using the third arg to the
overload sub (a) is tedious (b) will lead to mistakes (c) makes the feature
feel unnatural.
With x~~ and ~~x, ~~ could become a deprecated fallback during the transition.
Writing sample code that overloaded ~~ really made this clear. (See my
previous post.)
> > but it has the practical benefit of keeping autodie working.
> [...]
> But if I understand the problem correctly, it’s not the code of autodie
> itself, it’s the interface that autodie has advertised so far, i.e. the
> cost we’re talking about isn’t patching autodie itself, it is patching
> all of the users of the autodie smartmatch interface. Is that correct?
That is correct. autodie enthusiastically embraced ~~, encourating users to
write:
given ($@) {
when (undef) { say "No error"; }
when ('open') { say "Error from open"; }
when (':io') { say "Non-open, IO error."; }
when (':all') { say "All other autodie errors." }
default { say "Not an autodie error at all." }
}
--
rjbs
Thread Previous
|
Thread Next