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<?php
/*
* Test to confirm the semantics of the & operator in various contexts
*
* phc -- The PHP compiler
*/
/*
* assignment ::= variable '&'? expr
*/
$base = 1;
$ref =& $base;
var_dump($base); // int(1)
var_dump($ref); // int(1)
$ref = 2;
var_dump($base); // int(2)
var_dump($ref); // int(2);
/*
* array_elem ::= expr? '&' expr
*/
$base_1 = 3;
$base_2 = 4;
$ref = array(1 => &$base_1, 2 => &$base_2);
var_dump($ref); // [1]=>&int(3) [2]=>&int(4)
$base_1 = 5;
$base_2 = 6;
var_dump($ref); // [1]=>&int(5) [2]=>&int(6)
$ref[1] = 7;
$ref[2] = 8;
var_dump($ref); // [1]=>&int(7) [2]=>&int(8)
var_dump($base_1); // int(7)
var_dump($base_2); // int(8)
$base_3 = 9;
$ref[2] =& $base_3;
var_dump($ref); // [1]=>&int(7) [2]=>&int(9)
/*
* foreach ::= expr VARIABLE '&' VARIABLE statement*
*
* Note the difference in the structure after the second foreach
* (I do not know whether this is something we need to mimick)
*/
$arr = array(1 => 11, 2 => 12);
var_dump($arr); // [1]=> int(11) [2]=> int(12)
foreach($arr as $key => $val) { $key += 10; $val *= 2; }
var_dump($arr); // [1]=> int(11) [2]=> int(12)
foreach($arr as $key => &$val) { $key += 10; $val *= 2; }
var_dump($arr); // [1]=> &int(22) [2]=> &int(24)
foreach($arr as $key => &$val) { $key += 10; $val *= 2; }
var_dump($arr); // [1]=> &int(44) [2]=> &int(48)
/*
* formal_parameter ::= IDENT? '&'? VARIABLE static_scalar?
*
* Note that the global keyword overrides the & in function f3.
*/
$x = 2;
function f1($par)
{
var_dump($par);
$par *= 2;
}
f1($x); // int(2)
var_dump($x); // int(2)
function f2(&$par)
{
var_dump($par);
$par *= 2;
}
f2($x); // int(2)
var_dump($x); // int(4)
function f3(&$par)
{
global $par;
var_dump($par);
$par *= 2;
}
f3($x); // NULL
var_dump($x); // int(4)
/*
* signature ::= '&'? IDENT formal_parameter*
*
* Note the difference between the lines marked [*] and [**]
*/
function f4()
{
static $in_f4 = 0;
$in_f4++;
return $in_f4;
}
$out_f4 = f4();
var_dump($out_f4); // int(1)
$out_f4 = f4();
var_dump($out_f4); // int(2)
$out_f4 = 10;
var_dump($out_f4); // int(10)
$out_f4 = f4();
var_dump($out_f4); // int(3)
$out_f4 =& f4();
var_dump($out_f4); // int(4)
$out_f4 = 10;
var_dump($out_f4); // int(10)
$out_f4 = f4();
var_dump($out_f4); // int(5) [*]
function &f5()
{
static $in_f5 = 0;
$in_f5++;
return $in_f5;
}
$out_f5 = f5();
var_dump($out_f5); // int(1)
$out_f5 = f5();
var_dump($out_f5); // int(2)
$out_f5 = 10;
var_dump($out_f5); // int(10)
$out_f5 = f5();
var_dump($out_f5); // int(3)
$out_f5 =& f5();
var_dump($out_f5); // int(4)
$out_f5 = 10;
var_dump($out_f5); // int(10)
$out_f5 = f5();
var_dump($out_f5); // int(11) [**]
/*
* actual_paramter ::= '&' VARIABLE
*
* Note the discrepency between this and the previous test.
* - If a function _returns_ a symbol table entry, the associated assignment
* must also be =& (and not just =; cf. test above)
* - For a function to _accept_ a symbol table entry, there is a choice:
* either you add the & to the formal parameter, or you add the & to the
* actual parameter (both is allowed too).
*/
function h1($in_h1)
{
$in_h1++;
}
$out_h1 = 5;
h1(&$out_h1);
var_dump($out_h1); // Outputs 6
function h2(&$in_h2)
{
$in_h2++;
}
$out_h2 = 5;
h2(&$out_h2);
var_dump($out_h2); // Outputs 6
?>
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