Did this topic end nowhere?
Isn't some fix here better than no fix?
class-constants are currently compile-time constants and letting them
use constants from classes defined in other files will move them to
run-time constants (because php has ambiguity-feature of
conditional-loading), so, probably, this part should be skipped
anyway.
On 9/10/07, Marcus Boerger <[EMAIL PROTECTED]> wrote:
> Hello Dmitry,
>
> This is a good catch. I gave it a bit of attention some time ago and it is
> not trivial to fix. However code often improves from this. Most of all
> ofeten enough you end up with some consts that would in other languages be
> enums like:
> class Week {
> const Monday = 0;
> const Tuesday = Monday + 1;
> // ...
> }
> or this:
> class Logging {
> const INFO = 0;
> const WARN = INFO + 1;
> const FAIL = WARN + 1;
> // ...
> }
>
> I'd especially like this because it would make my enum implementation in
> pecl/spl_types more handy.
>
> marcus
>
> Monday, September 10, 2007, 9:55:49 AM, you wrote:
>
> > I see a problem with this idea.
> > In case we support constant expressions, we should support constants in such
> > expressions, but the values of these constants may be unknown in compile
> > time.
>
> > <?php
> > class Foo {
> > const A = 0;
> > }
> ?>>
>
> > <?php
> > require_once "foo.php";
> > class Bar extends Foo {
> > const B = self::A + 1;
> > }
> ?>>
>
> > Delaying constant initialization for expressions in general will require
> > keeping of Abstaract Syntax Tree, that should be evaluated at run-time by
> > zval_update_constant().
>
> > Thanks. Dmitry.
>
> >> -----Original Message-----
> >> From: Nuno Lopes [mailto:[EMAIL PROTECTED]
> >> Sent: Saturday, September 08, 2007 10:50 PM
> >> To: Stanislav Malyshev
> >> Cc: internals@lists.php.net; [EMAIL PROTECTED]; [EMAIL PROTECTED]
> >> Subject: Re: Re: [PHP-DEV] constant folding optimization
> >>
> >>
> >> >> I made a patch to implement constant folding optimization in the
> >> >> Zend engine.
> >> >> The patch is available at:
> >> >> http://web.ist.utl.pt/nuno.lopes/zend_constant_folding.txt
> >> >
> >> > I like the idea a lot, however I think this patch has one
> >> > significant downside - as far as I understand, it doesn't enable
> >> > constant expressions in constant contexts. I.e. I can do $a = 2+2
> >> > and get it evaluated but I can't do function foo($a = 2+2)
> >> or const
> >> > $a = 2+2. If we moved this to the parser level I think we could do
> >> > both.
> >>
> >> Well we don't support that syntax at this moment. If you are saying
> >> that we could add support for such syntax.. it does seem a
> >> good idea,
> >> but in that case we would need to modify a few rules of the grammar
> >> (like adding a const_expr production, and allow static_scalar derive
> >> it, etc..).
> >>
> >> If others agree with this syntax, I can take a look in
> >> implementing it.
> >>
> >> Nuno
> >>
> >> --
> >> PHP Internals - PHP Runtime Development Mailing List
> >> To unsubscribe, visit: http://www.php.net/unsub.php
> >>
>
>
>
>
> Best regards,
> Marcus
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>
--
Alexey Zakhlestin
http://blog.milkfarmsoft.com/
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
