Question

Example:

$var = 'post_type_archive';
$name = 'some-archive';
$condition = 'is_'.$var;
if($condition($name)) 

Is that considered a big fat no-no? If so, how else could one accomplish something similar?

Answer 1

It is not a bad practice when you limit the usage to certain cases. One of these cases might be dynamically calling functions based on the given GET parameters.

But I would recommend to use call_user_func() instead. It makes clear what you are going to do and the code is much more readable. Remember to always check the existence of the function with is_callable().

call_user_func() will not work with built-in functions though.