Declare a Function in PHP Using a String?

Question

Invalid code:

$functionName = 'sayThis';

function $functionName($string) {
    echo $string;
}

Can I do anything like this?

Would help to understand why you want to do this. What are you trying to accomplish? — Mads Mobæk
– Mads Mobæk, Commented Nov 29, 2009 at 0:20
I have the same function (processFormSubmission()) in many files. The function currently has one name, but does several different things depending on the file it is in. Sometimes the same function name can be included in one execution. If this is the case, I get an error saying that the function has already been declared. I want to dynamically name the function so I don't have name clashes. The dynamically assigned name of the function will be stored in a class. — Kirk Ouimet
– Kirk Ouimet, Commented Nov 29, 2009 at 8:03

Ewan Todd · Accepted Answer · 2009-11-28 23:55:16Z

3

call_user_func and call_user_func_array do something similar. Use sparingly and judiciously.

answered Nov 28, 2009 at 23:55

Ewan Todd

7,33229 silver badges35 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

I want to dynamically declare the function name

Atli · Accepted Answer · 2009-11-29 00:13:35Z

2

I don't recommend you do this, but if you insist, using eval is an option.
Be extremely careful tho. And keep it far far away from any user input!

<?php
$name = 'sayThis';

$code = <<<PHP
function $name(\$string) {
    echo \$string;
}
PHP;
eval($code);

$name('This is NOT a good idea!');
?>

answered Nov 29, 2009 at 0:13

Atli

7,9492 gold badges34 silver badges44 bronze badges

+1 This looks like it answers the OP's question. It is one of those things to be careful what you ask for.