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Reply-To: "Sara Golemon" <pollita@php.net>
To: <internals@lists.php.net>
Date: Wed, 23 Nov 2005 14:39:30 -0800
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Subject: Labeled Breaks (not the G-word)
From: pollita@php.net ("Sara Golemon")

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