Okay I'll try and look at your patch in the next couple of days.
It's quite sensitive code which this changes (has harmless as it might
seem) so I need some time to read over it.
Andi
At 11:37 29/05/2002 -0500, Jason T. Greene wrote:
>Andi,
>
>I do not see how this is semantically incorrect, or how it is that much
>different than allowing default values for pass by reference arguments.
>IMO The only useful reason to deny passing a constant/expression in a
>function is to provide a warning message. Some of the problems I
>outlined in my post can be solved using default values(only using ZE2,
>which allows defaults on reference args); however, default values only
>solve rightmost optional parameters. i.e. there is no way to do:
>
>function a($arg1, $arg2="blah", $arg3="blah"){}
>
>
>a(1, ,3)
>
>In respect to not passing by reference, this problem is solved by doing
>the following
>
>function magic_function($var1, $var2, $var3) {
> // Note just an example - I would usually use func_get_args...
> if ($var2 === NULL) {
> $var2 = "blah";
> }
>}
>
>magic_function(1, NULL, 3);
>
>This technique of course will not work with the current semantics of not
>allowing constants/expressions to pass by reference.
>
>-Jason
>
>
>
>
>
>On Wed, 2002-05-29 at 10:26, Andi Gutmans wrote:
> > I don't see any reason to allow passing non-variables by reference.
> > It is semantically incorrect.
> >
> > Andi
> >
> > At 09:40 29/05/2002 +0200, Stig S. Bakken wrote:
> > >If this patch doesn't break anything, and it doesn't give us any
> > >difficulties with ZE2 or major design issues, I'm +1.
> > >
> > > - Stig
> > >
> > >On Tue, 2002-05-28 at 21:12, Jason T. Greene wrote:
> > > > Due to this patch being sent during the msession discussion, it has not
> > > > been noticed, so I am resending.
> > > >
> > > >
> > > > -Jason
> > > > ----
> > > >
> > >
> > > > From: Jason Greene <[EMAIL PROTECTED]>
> > > > To: [EMAIL PROTECTED]
> > > > Cc: [EMAIL PROTECTED], [EMAIL PROTECTED]
> > > > Subject: [PHP-DEV] [PATCH] Allow constants / expressions to be passed
> > > by reference
> > > > Date: 25 May 2002 02:18:52 -0500
> > > >
> > > > Problem
> > > > -------
> > > >
> > > > There are some scenarios where a function requires the ability to
> modify
> > > > parameters that may also be optional. Optional parameters work well,
> > > > except in the scenario where all of the pass by reference
> parameters can
> > > > be optional. ex the socket_select() function. Since select is
> > > > argument-result, all three arrays that are taken as input must be
> passed
> > > > by reference, yet any can be excluded. So for example if you were
> > > > calling socket_select with a read socket array, a write socket array,
> > > > yet no exception array (quite common), you are currently forced to do
> > > > something like the following:
> > > >
> > > > $wfds = array($sock1, $sock2);
> > > > $rfds = array($sock3, $sock4);
> > > > $null = NULL;
> > > >
> > > > socket_select($rfds, $wfds, $null);
> > > >
> > > >
> > > > I have ran into this problem before several times while developing in
> > > > user space. (Especially when passing around semi-complex data
> > > > structures)
> > > >
> > > > Proposed Solution
> > > > ------------------
> > > >
> > > > Allow all expressions to be passed by reference. This will allow
> > > > something like the following
> > > >
> > > > function normalize(&$element_tree, &$node_mapping, $max_depth){
> > > > //Code
> > > > }
> > > >
> > > > normalize($my_tree, NULL, 25000);
> > > >
> > > >
> > > > Patch
> > > > ------
> > > >
> > > > I have attached a patch against ZE2 that accomplishes this.
> > > >
> > > >
> > > > Thanks,
> > > > -Jason
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ----
> > > >
> > >
> > > > Index: zend_compile.c
> > > > ===================================================================
> > > > RCS file: /repository/ZendEngine2/zend_compile.c,v
> > > > retrieving revision 1.285
> > > > diff -u -r1.285 zend_compile.c
> > > > --- zend_compile.c 23 Apr 2002 18:06:53 -0000 1.285
> > > > +++ zend_compile.c 25 May 2002 06:45:21 -0000
> > > > @@ -1271,7 +1271,7 @@
> > > > op = ZEND_SEND_REF;
> > > > break;
> > > > default:
> > > > - zend_error(E_COMPILE_ERROR, "Only
> > > variables can be passed by reference");
> > > > + op = ZEND_SEND_VAR;
> > > > break;
> > > > }
> > > > }
> > > > Index: zend_execute.c
> > > > ===================================================================
> > > > RCS file: /repository/ZendEngine2/zend_execute.c,v
> > > > retrieving revision 1.341
> > > > diff -u -r1.341 zend_execute.c
> > > > --- zend_execute.c 8 May 2002 18:43:19 -0000 1.341
> > > > +++ zend_execute.c 25 May 2002 06:45:25 -0000
> > > > @@ -2292,10 +2292,6 @@
> > > > NEXT_OPCODE();
> > > > }
> > > > case ZEND_SEND_VAL:
> > > > - if
> > > (EX(opline)->extended_value==ZEND_DO_FCALL_BY_NAME
> > > > - &&
> > > ARG_SHOULD_BE_SENT_BY_REF(EX(opline)->op2.u.opline_num, EX(fbc),
> > > EX(fbc)->common.arg_types)) {
> > > > - zend_error(E_ERROR,
> > > "Cannot pass parameter %d by reference", EX(opline)->op2.u.opline_num);
> > > > - }
> > > > {
> > > > zval *valptr;
> > > > zval *value;
> > > > @@ -2329,7 +2325,8 @@
> > > >
> > > zend_ptr_stack_push(&EG(argument_stack), varptr);
> > > > NEXT_OPCODE();
> > > > }
> > > > - zend_error(E_ERROR, "Only
> > > variables can be passed by reference");
> > > > + /* Should only occur with an
> > > uninitialized variable */
> > > > + goto send_by_var;
> > > > }
> > > > NEXT_OPCODE();
> > > > case ZEND_SEND_VAR:
> > > >
> > > > ----
> > > >
> > >
> > > > --
> > > > PHP Development Mailing List <http://www.php.net/>
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> > > > ----
> > > >
> > >
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> >
> >
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