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Date: Wed, 23 Nov 2005 21:02:57 -0800
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Subject: Re: Labeled Breaks (not the G-word)
From: pollita@php.net ("Sara Golemon")

Set of tests available too now:
http://libssh2.org/patches/labeled_break_tests.tgz

It can be untarred from the root of a PHP dist and it'll unfold into 
Zend/tests/break/

> http://libssh2.org/patches/labeled_break.diff
>
> A few notes about the implementation:
>
> * The parser is modified slightly to catch T_BREAK T_LNUMBER ';' and 
> T_BREAK
> T_STRING ';' specifically.  This is in-line with the decision to remove 
> the
> ability to jump to variable targets.  e.g. `break $foo;` will result in an
> E_PARSE.
>
> * current break container is moved from op1.u.opline_num to extended_value
> (This means updating continue; as well)
>
> * op1 is used to store the label's name until pass_two(), at that point 
> it's
> converted to a jmp_addr.  Non-labeled breaks leave op1 unused and jmp_addr
> explicitly set to NULL
>
> * zend_brk opcode handler updated to use op1->u.jmp_addr if available
> (labeled breaks), or el->brk (numbered breaks) if not.  zend_brk and
> zend_cont both updated per current break container change above.
>
> * Labeled breaks must target the same break container or higher within the
> same op_array, and must only jump "forward" in execution.  These checks 
> are
> handled in pass_two() which is the earliest point at which all labeled are
> declared.
>
> * Label hash is only allocated/initialized if labels are declared.
>
> Known Issues:
>
> * When an error is thrown from pass_two(), the error message states it's 
> in
> Unknown on line 0.  Gotta find a better way to handle that....
>
> * This adds an element to zend_op_array so be sure to either `make clean` 
> or
> at least `touch Zend/*.c` after applying it otherwise you'll be in 
> segfault
> country.
>
> -Sara