PHP Dynamic Duck Typing Without Eval

Question

Example:

<?php
class a{
    public function func(){
        return "a";
    }
}

class b{
    public function func(){
        return "b";
    }
}

$input = "a"; // Would come from user input

eval('$duck = new '.$input.'();');
$duck->func(); // Returns a in this case

Is there any way I can do this without using eval()?

Please refer this : http://stackoverflow.com/questions/951373/when-is-eval-evil-in-php — Anup Yadav, Dec 07 '12 at 06:47

score 8 · Accepted Answer · answered Dec 07 '12 at 06:47

8

Of course you can do it without eval(). PHP will take either a string containing the class name or the literal as an argument to the new operator.

$duck = new $input; // parentheses are optional
echo $duck->func();

answered Dec 07 '12 at 06:47

Ja͢ck

170,779
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2

I've been coding PHP for almost a year now, and PHP OOP for about a month. I never expected it to be that easy. – Dec 07 '12 at 07:03

score 1 · Answer 2 · answered Dec 07 '12 at 06:47

1

Yes you can by storing the class name into a string, for example :

$input = "a";
$duck = new $a();
if(is_callable($duck',"func")){
   $duck->func();
}

would work

answered Dec 07 '12 at 06:47

artragis

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PHP Dynamic Duck Typing Without Eval

2 Answers2