Front page | perl.perl5.porters |
Postings from August 2012
On 8/26/12, Father Chrysostomos <sprout@cpan.org> wrote:
...
> The third one actually has nothing to do with smart match at all. It’s a
> ‘when’ problem. If we really really don’t want to have to write
> when($_==3), then we could copy the precedent set by flipflop and split.
>
> if (1..2) means if ($.==1 .. $.==2)
> split ' ' is special
> $x = ' '; split $x does something different
>
> and implement two syntactic special cases:
>
> # literal numbers
> when(0)
> when(1)
> when(0xff)
> when(0b101110)
> when(023476)
> # literal strings
> when('foo')
> when("foo")
> when(q "foo")
> when(qq "foo")
>
> and *nothing* else. Everything else would be a boolean, including
> when($foo). Anything else is madness; it really is.
>
> Then we can just deprecate ~~.
>
> Those who say they want
>
> when(num(3))
>
> can write
>
> sub num { $_ == $_[0] }
>
> instead of
>
> sub num { my $arg = shift; sub { $_[0] == $arg } }
>
> which I think is an improvement.
>
> But that doesn’t work with lexical $_, so let’s deprecate that, too.
>
> (And make when do a simple next, and make given respond to next.)
+1 re: when
I don't have an opinion about deprecating smartmatch; I don't expect
to ever use it.
If I know 'when' will never do an implicit smartmatch, then I'll use 'when'.
I'd be happy if
when ( ... ) { ... }
were simply a synonym for
if ( ... ) { ... ;next}
but the above special cases are fine with me--I'd probably use them.
BTW, perlsyn in Perl 5 version 16.0 documentation
(http://perldoc.perl.org/perlsyn.html#Switch-Statements) says,
At the end of all when blocks, there is an implicit next. You can
override that with an explicit last if you're interested in only the
first match alone.
Note: "implicit next". Am I missing something? Does when already do a
simple next?
--
Brad
Thread Previous
|
Thread Next