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To: <internals@lists.php.net>, "Dmitry Stogov" <dmitry@zend.com>
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Date: Fri, 29 Aug 2008 08:35:49 -0500
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Subject: Re: [PHP-DEV] Re: [PATCH] Constant expr folding (again), and other things
From: php_lists@realplain.com ("Matt Wilmas")

Hi again Dmitry,

----- Original Message -----
From: "Dmitry Stogov"
Sent: Thursday, July 31, 2008

> Hi Matt,
>
> For now I would like to disable "-CONST" constant expression which
> started to work after your patch.
>
> Later we are able to implement the complete constant expressions support.

One more updated thing to ask about. :-)  From the last reply, I wasn't sure
if constant folding in zend_do_[binary|unary]_op() could be added (for
negative numbers, ORing function flags that were substituted, ~0, 1024 *
1024, etc.) or it was desired to wait for "complete constant expressions
support" (in static_scalar context), though I don't see any relation between
that, which is an actual language change, and this easy optimization that's
only internal (and more useful now with constant substitution).

So I updated the patch, which is the same code as before, but without trying
to add partial expression support to static_scalar.  Seems pretty
simple/safe, with basically just the if () {  } block added in
zend_do_[binary|unary]_op(). :-)  The rest updates the unary_op_type typedef
(was missing TSRMLS_DC), adds binary_op_type, and updates get_binary_op
(half the patch!).  The couple changes in the parser, which CAN be ignored
if desired, are mostly a cleanup, but  '+' static_scalar  now actually "does
something" like the unary + operator in regular contexts.  As I showed
before, it makes the following consistent:

function foo() {
    static $a = -'abc'; // 0
    static $b = +'abc'; // abc
    $c = +'abc'; // 0
}

http://realplain.com/php/const_folding.diff
http://realplain.com/php/const_folding_5_3.diff

Well, I don't know if it can be tossed in quickly at this time, but there ya
go since I think it's pretty basic! ;^)

> Thanks. Dmitry.

Thanks,
Matt