Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:81116
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.192.170 as permitted sender)
Message-ID: <54C4B467.3080200@gmail.com>
Date: Sun, 25 Jan 2015 01:16:23 -0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:31.0) Gecko/20100101 Thunderbird/31.3.0
MIME-Version: 1.0
To: Marc Bennewitz <dev@mabe.berlin>, internals@lists.php.net
References: <52243BA6.5040905@sugarcrm.com> <54B6C047.3070301@mabe.berlin>
In-Reply-To: <54B6C047.3070301@mabe.berlin>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] [RFC] Skipping parameters take 2
From: smalyshev@gmail.com (Stanislav Malyshev)

Hi!

> class Baz extends Bar {
>     function foo($a=default, $b=default) {
>         // do something
>         parent::foo($a, $b);
>     }
> }

I tried to implement this, however there's a major issue that I do not
know how to overcome. The issue is that when we compile method foo() we
do not know the default values. These values are stored in RECV_INIT
opcodes directly, so when we find out what the actual values are - i.e.
when we resolve inheritance for class Baz - it may be in runtime, so
we'd have to update opcodes for RECV_INIT in foo() in runtime. Which is
not going to sit well with opcode cache, which assumes opcodes do not
change.

I'm not sure yet how to solve this - since the values are only stored in
the opcodes it is not easy to locate them in runtime, so even if we make
'default' zvals some special type we'd still have a problem finding the
right value since the binding happens in runtime and we don't have now
any place to store the result of that binding.

I'll think a bit more about it, in the meantime any ideas about how to
resolve this problem are welcome.

-- 
Stas Malyshev
smalyshev@gmail.com