Magic methods get and set - example from ZCE

Question

 class Magic { public $a = "A"; protected $b = array("a" => "A", "b" => "B", "c" => "C"); protected $c = array(1,2,3); public function __get($v) { echo "$v, "; return $this->b[$v]; } public function __set($var, $val) { echo "$var: $val,"; $this->$var = $val; } } $m = new Magic(); echo $m->a.", ".$m->b.", ".$m->c.","; $m->c = "CC"; echo $m->a.", ".$m->b.", ".$m->c.",";

This is an example question (not from an actual exam) for ZCE. Can someone please explain to me... what's going on here, and why the answer is... not at all what I expected?

b, c, A, B, C,c: CC,b, c, A, B, C,

bwoebi · Accepted Answer · 2013-04-08 19:25:20Z

then… what do you expect?

It calls __get/__set if you don't have from your actual scope the rights to access the property / the property doesn't exist.

So $m->a gets directly "A"; $m->b and $m->c call first __get("b") and __get("c") (return "B" and "C" after echoing "b, c, ")

The same is for $m->c = "CC";: it calls __set("c", "CC") as $c is a protected (non-accessible) property. (sets $m->c to "CC" after echoing "c: CC")

because the string is first concatenated which needs to fetch (the echo in __set is instantly called on fetching; doesn't wait for completing the string concatenation) the values and only after reading the values, it outputs the string. (Try replacing the "." in the echo statement by ",". Then it's interpreted like if there were different echo statements.)

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