Re: "<->" as "->" with automatic "is rw"
Juerd <[EMAIL PROTECTED]> writes:
> Sick would be if <- were introduced to make the variable write-only ;)
Sicker still would be if - were introduced to make the variable
neither readable nor writeable. HTH.HAND.
--
$;=sub{$/};@;=map{my($a,$b)=($_,$;);$;=sub{$a.$b->()}}
split//,"[EMAIL PROTECTED]/ --";$\=$ ;-> ();print$/
Re: "<->" as "->" with automatic "is rw"
Larry Wall skribis 2004-08-20 13:31 (-0700): > Unfortunately I'm not sure it passes the "Are there already too many > ways to declare a sub?" test... I'm not seeing it as another way. Technically, of course it is different, but by the user, <-> and -> will probably be seen as one thing, with one of them being the other's specialized form. > It's really sick Sick would be if <- were introduced to make the variable write-only ;) W R @foos -> $foo @foos <-> $foo @foos <- $foo It would be consistent, though... Juerd
Re: "<->" as "->" with automatic "is rw"
On Fri, 20 Aug 2004, Larry Wall wrote:
> On Fri, Aug 20, 2004 at 10:07:02PM +0200, Juerd wrote:
> : I'm proposing
> :
> : for zip(@foos, @bars, @xyzzies) <-> $foo, $bar, $xyzzy { ... }
> : for %quux.kv <-> $key, $value { ... }
>
> That'd probably work on the keys only if the hash was declared to have
> object keys. At least in Perl 5, the key is always a copy.
>
> : to mean
> :
> : for zip(@foos, @bars, @xyzzies) -> $foo is rw, $bar is rw, $xyzzy is rw { ... }
> : for %quux.kv -> $key is rw, $value is rw { ... }
> :
> : Comments, anyone?
>
> It's really sick, and cute, and I love it. Unfortunately I'm not sure
> it passes the "Are there already too many ways to declare a sub?" test...
>
> It's vaguely possible I could be persuaded on the basis that
>
> for zip @a ¥ @b <-> { ($^a,$^b) = ($^b,$^a) }
>
> could be made to work. But I'm still dubious. And arguably -> {...}
> means the same as sub () {...}, implying there are no arguments.
Arguably it already means that. But if <-> were added, it might be a good
reason to make -> {...} mean -> $_ {...}, using <-> {...} for -> $_ is rw
{...}. A good way to remove one more special case (maybe offsetting the extra
way to declare a sub, and sweeten the whole deal).
--
Adam Lopresto
http://cec.wustl.edu/~adam/
Yesterday upon the stair
I met a man who wasn't there.
He wasn't there again today --
I think he's from the CIA.
Re: "<->" as "->" with automatic "is rw"
On Fri, 20 Aug 2004 13:49:46 -0700, Larry Wall <[EMAIL PROTECTED]> wrote: > Yes, a typo. Though it's not actually clear yet whether you have to > write zips args with semicolons, which is why I partially switched > to ¥ in midthink. Just checking. I wondered if you'd introduced a new feature midthink (and I'd missed it). -- matt
Re: "<->" as "->" with automatic "is rw"
On Fri, Aug 20, 2004 at 04:46:33PM -0400, Matt Diephouse wrote:
: On Fri, 20 Aug 2004 13:31:12 -0700, Larry Wall <[EMAIL PROTECTED]> wrote:
: > It's vaguely possible I could be persuaded on the basis that
: >
: > for zip @a ¥ @b <-> { ($^a,$^b) = ($^b,$^a) }
:
: Shouldn't that be:
:
: for zip @a, @b <-> { ... }
: --or--
: for @a ¥ @b <-> { ... }
:
: ?
Yes, a typo. Though it's not actually clear yet whether you have to
write zips args with semicolons, which is why I partially switched
to ¥ in midthink.
Larry
Re: "<->" as "->" with automatic "is rw"
On Fri, 20 Aug 2004 13:31:12 -0700, Larry Wall <[EMAIL PROTECTED]> wrote:
> It's vaguely possible I could be persuaded on the basis that
>
> for zip @a ¥ @b <-> { ($^a,$^b) = ($^b,$^a) }
Shouldn't that be:
for zip @a, @b <-> { ... }
--or--
for @a ¥ @b <-> { ... }
?
--
matt
Re: "<->" as "->" with automatic "is rw"
On Fri, Aug 20, 2004 at 10:07:02PM +0200, Juerd wrote:
: I'm proposing
:
: for zip(@foos, @bars, @xyzzies) <-> $foo, $bar, $xyzzy { ... }
: for %quux.kv <-> $key, $value { ... }
That'd probably work on the keys only if the hash was declared to have
object keys. At least in Perl 5, the key is always a copy.
: to mean
:
: for zip(@foos, @bars, @xyzzies) -> $foo is rw, $bar is rw, $xyzzy is rw { ... }
: for %quux.kv -> $key is rw, $value is rw { ... }
:
: Comments, anyone?
It's really sick, and cute, and I love it. Unfortunately I'm not sure
it passes the "Are there already too many ways to declare a sub?" test...
It's vaguely possible I could be persuaded on the basis that
for zip @a ¥ @b <-> { ($^a,$^b) = ($^b,$^a) }
could be made to work. But I'm still dubious. And arguably -> {...}
means the same as sub () {...}, implying there are no arguments.
Larry
"<->" as "->" with automatic "is rw"
I like that arguments will be readonly by default. But when I look at my
current code, I see that I would be typing " is rw" quite a lot, which in
my opinion is too long for a thing that occurs very often.
Every such situation in my code is a foreach loop. A thing that in Perl
6 will mostly be used with the pointy sub declaration syntax.
If I'm not mistaken, <-> is still available. It communicates
"bidirectional" and that is more or less the same as read/write access.
I'm proposing
for zip(@foos, @bars, @xyzzies) <-> $foo, $bar, $xyzzy { ... }
for %quux.kv <-> $key, $value { ... }
to mean
for zip(@foos, @bars, @xyzzies) -> $foo is rw, $bar is rw, $xyzzy is rw { ... }
for %quux.kv -> $key is rw, $value is rw { ... }
Comments, anyone?
Juerd
