> > Yeah, every once in a while, I've wanted the second layer, but I'm
> > willing to rewrite the statement as a true normal if/while instead of a
> > backwards if/while, and it *does* help the overall readability.
>
> I'd concede that the actual useful uses are rare enough to not warrant
> giving a feature that could turn hopelessly ugly quickly - even if the
> current generation of tools make it easy to add the feature.
Sorry to respond to my own post. As soon as I sent the reply I still felt an
itch for a second level.
I agree that such a thing could be abused as Randal mentioned. But how many
things are there in Perl 5 and Perl 6 that can't be abused (sorry - that is a
sort of subjective thing to ask so I am putting it out hypothetically)? It
still seems odd to take some things out of the language but leave others in
(ok - most things that have been left out have made perfect sense). I'm much
more a fan of the leaving in if the thing being left in doesn't have an
exponential cost and if there isn't a good reason to exclude it.
We still have goto statements. We have map and grep that now go forwards -
but can still go backwards.
Taking it out doesn't necessarily prevent abuses since we now have repeat.
repeat {
repeat {
say "Oh no. Not again";
} while $x++ < 10;
} while $y++ < 2;
As opposed to
say "Yes. Yes again"
while $x++ < 10
while $y++ < 2;
Additionally reading the documentation about repeat it seems that the
following should already be allowed since the conditional statement on a
repeat is not optional and if it doesn't come first then it MUST come later
and if it MUST come later then it isn't a modifier.
my $x = 1; repeat { say "hello"; $x = 0 } while $x if $x;
Though I would expect the following to break because it wouldn't know to parse
for the modifier after the closing brace:
my $x = 1; repeat while $x { say "hello"; $x = 0 } if $x;
This is what pugs does - though I'm not sure what it means.
pugs> my $x = 1; repeat { say "hello"; $x = 0 } while $x;
hello
0
pugs> my $x = 1; repeat { say "hello"; $x = 0 } while $x if $x;
....>
I think it means that I will probably need to have the correct behavior be
clarified to me, obtain a commit bit and add a test to pugs.
Anyway. Once again if the alleged crime or the predicted crime is too great
then I concede. I can see that it could be abused by some. But that doesn't
mean I will abuse it.
Paul
PS. And not that it matters, but TT3 is planned to support nested statement
modifiers and my engine which does much of TT3 already supports them - and I
do use them on occasion - but that's a different mailing list.
