Question

In PHP I’d like to do this:

switch (function_foo($bar,$bar2)) {
case $fu:
    *Do Stuff*
    break;
case $fubar:
    *Do Other Stuff*
    break;
}

Is this a terrible idea? Will it work?

Answer 1

Using a function in the switch is OK : the function will be called, and will return a value — which is the one that will be used for the case.

It’s exactly the same as writing :

$my_var = function_foo($bar,$bar2);
switch ($my_var) {
    // ...
}

Even if I prefer using a variable, so the code is easier to read.

And using variables in the `case` is something you don’t see often ; but it works fine too 😉

Quoting the manual page of switch :

The case expression may be any
expression that evaluates to a simple
type, that is, integer or
floating-point numbers and strings.

So, your code will work, as long as $fu and $fubar contain simple-type values.

Using a variable as a `case` value not often done *(as far as I can tell from the code I read)*, probably because some other languages don’t allow that *(for instance, C doesn’t allow that ; and the `switch`/`case` structure is borrowed from C)* ; but it works :

$a = 1;
$b = 2;
switch (1) {
    case $a: echo 'a'; break;
    case $b: echo 'b'; break;
}

Will output :

a