Question

Let’s say that I have a function that should only execute if some constant is defined. which of the following would be better

Option 1: wrap all the function calls in an if block:

if(defined('FOO_BAR_ENABLED')) {
   foobar();
}

I figure this way the intent is more clear, but it requires checking the constant every time the function is called.

Option 2: check the constant in the function itself:

function foobar() {
  if(!defined('FOO_BAR_ENABLED')) {
    return;
  }
  //do stuff 
}

This way requires less lines of code, and the constant is sure to get checked. However, I find it confusing to see calls to this function when it’s not actually doing anything. Thoughts?

Answer 1

May I suggest renaming the function to FoobarIfEnabled(), then doing the check in the function?

Stealing liberally from a great language-agnostic answer to one of my own questions, when programming we have the following concerns:

1. Make it correct.
2. Make it clear.
3. Make it concise.
4. Make it fast. … in that order.

If you do the check outside the function, you might end up missing it in one place. And if you want to change the behavior, you’ll have to find all the places it gets called and fix it. That’s a maintenance nightmare which violates principle 1. By adding “IfEnabled” or something like that to the name, now it is not just correct but also is clear. How can you beat that?

Performance is not to be worried about unless the final speed is unsatisfactory and you have identified this as the bottleneck (unlikely).

I recommend you follow the link above and read as it was a very useful answer that gave me much to think about.