Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:10172
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Message-ID: <20040529141411.11566.qmail@pb1.pair.com>
To: internals@lists.php.net
References: <40B76426.8080107@php.net> <40B7A984.6070702@actcom.net.il> <40B7B4EB.4080208@php.net> <40B82E44.2000409@actcom.net.il> <40B843DA.3080403@leetspeak.org> <40B85C1B.6010305@actcom.net.il>
Date: Sat, 29 May 2004 07:15:47 -0700
Lines: 28
Subject: Re: [PHP-DEV] switch labels in sub-blocks
From: pollita@php.net ("Sara Golemon")

> Well, now that I think I understand what is it for,
> I'm pretty sure it's not very appropriate for PHP(,
> unless someone will provides an example of the opposite
> of course).
>
> It's kind of clarity vs efficiency.
> The more the basic operation ("*to = *from++" in the
> original) is getting bigger (slower) the efficiency gain becomes
> smaller (correct?) so I would prefer clarity here.
>
> I'm not even sure real example in PHP will have close to 50%
> speed gain.
>
In the case of "Duff's Device" it certainly isn't applicable to PHP....It
much for efficient for the engine to process a complex single opcode than to
process many simple opcodes in succession.  That still doesn't speak to
whether or not there aren't truly applicable examples.

Functionally the parser doesn't want to see overlapping structures like this
and it feel non-trivial to implement.  But I havn't looked at the switch
implementation close enough to be certain yet.

For the sake of readability I'm -1.  I'd sooner see goto implemented than
this.  And I don't care for that either.

-Sara