Hi Sara,
I didn't like "goto" in PHP, but after looking in this patch I see that
limited "goto" can work.
1) The new syntax makes mess for me.
"break" is a statement that exits from loop or switch, now we make a "goto"
statement but name it "break".
I belive that if we really implement goto (even with some limitations) we
shuld name it "goto", but not "break".
(changed in attached patch).
2) After (1) I don't see any reason in limitation to jump only down, if we
can jump up as well. (the limitation is removed in attached patch).
2) Your patch doesn't care about freeing loop variables and we got a memory
leaks in the following example (this is fixed in attahed patch).
<?php
foreach (array(1,2,3) as $v) {
break LABEL;
}
LABEL:
?>
3) You can declare one LABEL twich. This should emit comilation error. (this
is fixed in attached patch).
4) Keeping "labels" field in op_array after compilation make not sense as it
used only during compilation and not during execution. (this is fixed in
attached patch) May be we should place this HashTable somewere outside of
op_array.
Now I don't see inconsistencies.
But I still not sure that PHP needs "goto".
Thanks. Dmitry.
> -----Original Message-----
> From: Sara Golemon [mailto:[EMAIL PROTECTED]
> Sent: Thursday, November 24, 2005 8:03 AM
> To: internals@lists.php.net
> Subject: [PHP-DEV] Re: Labeled Breaks (not the G-word)
>
>
> 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
>
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