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Thread-Topic: Accessors Parsing
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Date: Tue, 8 Nov 2011 14:26:44 +0000
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Subject: Accessors Parsing
From: cpriest@zerocue.com (Clint M Priest)

Working to implement Getter/Setter Accessor syntax as per https://wiki.php.=
net/rfc/propertygetsetsyntax but brand new to php internals development.

I was planning on having the parser define methods on the class for the get=
ter/setter such as __getHours() and __setHours() and then have those functi=
ons called in leiu of __get() if they are defined, does that seem like a re=
asonable strategy for this?

More specific problems on the parser side of things, here is what I have no=
w:

getter_setter_declarations:
		getter_declaration
	    setter_declaration
	|   setter_declaration
	    getter_declaration
	|   setter_declaration
	|   getter_declaration
	|   /* empty */
;

getter_declaration:
	method_modifiers T_GET
		{ zend_do_begin_function_declaration(&$2, &$$, 1, ZEND_RETURN_VAL, &$1 TS=
RMLS_CC); }
			'{' inner_statement_list '}'
		{ /******** $$ !=3D Hours Here!! ***************/
		 zend_do_abstract_method(&$$, &$1, &$4 TSRMLS_CC); zend_do_end_function_d=
eclaration(&$2 TSRMLS_CC); }

setter_declaration:
	T_SET '{' inner_statement_list '}'

class_variable_declaration:
		T_VARIABLE { $$ =3D $1; /**** Capture variable name ****/ } '{' getter_se=
tter_declarations '}'
	|	class_variable_declaration ',' T_VARIABLE					{ zend_do_declare_property=
(&$3, NULL, CG(access_type) TSRMLS_CC); }
	|	class_variable_declaration ',' T_VARIABLE '=3D' static_scalar	{ zend_do_=
declare_property(&$3, &$5, CG(access_type) TSRMLS_CC); }
	|	T_VARIABLE						{ zend_do_declare_property(&$1, NULL, CG(access_type) TS=
RMLS_CC); }
	|	T_VARIABLE '=3D' static_scalar	{ zend_do_declare_property(&$1, &$3, CG(a=
ccess_type) TSRMLS_CC); }
;

I'm just working on the getter now.=20

 1) I am able to get the T_VARIABLE name passed through to the zend_do_begi=
n_function() using $$ however $$ is no longer correctly set by zend_do_abst=
ract_method().  What would be a more appropriate way to store the variable =
znode?  I see there are a number of stacks in the compiler_globals, would u=
sing one of those or creating a new one be appropriate?

 1.1) Alternatively to #1, is there a way to access the T_VARIABLE znode fr=
om the zend_do_begin_function_declaration() line?   (Reach re patterns from=
 previous/prior matches/lines)

2)  I am having trouble with building the function name (2nd param to zend_=
do_begin_function) since that function needs to have a znode as the input. =
 I could stuff code in here to concat the strings together and build a znod=
e but since there is sparsely any real code in this file I hesitate to do s=
o.  Any recommendations here?=20

3) An interesting situation with the above code is that the function is dec=
lared and is seen through a ReflectionClass() but calling it indicates that=
 the function does not exist, I think that is because $$ was cleared/change=
d by the time zend_do_abstract() is called, is this something I should add =
a check for?  (Calling zend_do_abstract() with a function name that was not=
 previously seen via zend_do_begin_function_declaration())

For reference, here is the PHP test class I am using:

#!/opt/trunk/sapi/cli/php
<?php
class TimePeriod {
=09
	public $Seconds;

	public function __construct($Seconds) {
		$this->Seconds =3D $Seconds;
	}
	public $Hours {
		get {
			return $this->Seconds / 3600;
		}
	/*	set { $this->Seconds =3D $value * 3600; } // The variable $value holds =
the incoming value to be "set"*/
	};
}

$o =3D new TimePeriod(3600);

echo $o->Seconds."\r\n";
echo $o->Hours()."\r\n";

?>