Jonathan Scott Duff writes:
> On Wed, Nov 19, 2003 at 12:49:21PM -0800, Larry Wall wrote:
> > Sorry, I wasn't being very clear. It wouldn't be logically attached to
> > the outside of the for, but to the inside of the "confer", or whatever:
> >
> > @foo = gather {
> > for @a -> $x { pick $x if mumble($x) }
> > DEFAULT { @results }
> > }
>
> So ... the only way to get Damians semantics ...
>
> On Wed, Nov 19, 2003 at 08:01:40AM +1100, Damian Conway wrote:
> > * vector control structures like C<loop>, C<while>, and C<for> in
> > a list context return a list of the values of the last statement
> > each iteration evaluated;
> >
> > * vector control structures like C<loop>, C<while>, and C<for> in
> > a scalar context return an integer indicating the number of
> > times their block was iterated.
>
> ... is to surround the control structure with a gather { ... } ??
No. gather{} is a generator (assuming nothing about its name or
existance whatsoever). It runs some code, gathering up each pick()
(same assumption) into a list, and returning that.
If I interpret Larry correctly, Damian's semantics won't be going in.
The way you get each of those is:
my @list = gather {
while $cond {
pick do {...}
}
}
And similarly for each of the other constructs.
But Damian's semantics will work for simple conditionals, it seems.
One wonders what the return value of a loop will be:
my $what = do {
while $cond {...}
}
Luke
> It seems like "gather" or whatever should be some sort of modifier to
> for/loop/while/until
>
> @foo = for : gather @a -> $x { ... }
> if for : gather @a -> $x { ... } < 3 { ... } # ick!
> if : gather for : gather @a -> $x { ... } < 3 { ... } # ick!**2
> for : gather @a -> $x { ... } or @results;
> for : gather @a -> $x { ... } or do { ... }
>
> Okay, so the syntax isn't great. I'm just brainstorming.
>
> Having a gather block just feels wrong to me. It's weird to say that
> control structure X only has a result when placed inside of a special
> block. But maybe it *needs* to be weird.
>
> > On the other hand, putting the default up front is clearer if the
> > block is long. Could even be something like:
> >
> > @foo = gather is default(@results) {
> > for @a -> $x { pick $x if mumble($x) }
> > }
>
> Hmm.
>
> @foo = for :gather,default(@results) @a -> $x { ... }
>
> -Scott
> --
> Jonathan Scott Duff
> [EMAIL PROTECTED]
