1

I would like to know your opinion on using return and else statements interchangeably in CFScript. I generally use the following syntax:

if (something) {
  // Do something
}
else {
  // Do something else
}

It recently occurred to me I could do this instead:

if (something) {
  // Do something
  return;
}
// Do something else

Would those two styles yield a different end result? I like not having to wrap code in an else statement. My thinking is that if the if statement evaluates true and returns, the code below it will not run. If it does not evaluate true, then the code below it will run regardless of whether it is wrapped in an else statement or not.

Does that sound right?

Mohamad
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    Yes, as long as you use a `return` that is correct. If it is one or two lines of code, I prefer the second method. But for more than that, the first method is more readable/intuitive IMO. – Leigh Jan 07 '11 at 19:56
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    See http://stackoverflow.com/questions/36707/should-a-function-have-only-one-return-statement for an exhaustive discussion of this idea across all programming languages. Your example #2 is called a "Guard Statement" by Fowler. – orangepips Jan 07 '11 at 20:17
  • @orangepips +1 for the awesome thread – Leigh Jan 07 '11 at 20:28
  • @orangepips thank you for the great post. It was a great read! – Mohamad Jan 07 '11 at 20:52

2 Answers2

4

Coldfusion like most languages provides many ways of accomplishing the same thing. The job of the programmer is to pick the correct one for the situation. Of course "correct" can have many interpretations but I would say the correct way is clear, concise and scalable.

In this case there are no real performance or "lines of code" differences. Using a return for an entirely different branch of code is not clear to my eyes however, using early return style to bail out of a function due to invalid conditions is (again IMO) more clear. Consider the following cases:

if (not isdefined("url.param1")) {
  return;
}
if (not len(url.param1)) {
  return;
}
if (not refind("[0-9]+", url.param1)) {
  return;
}
doSomethingToValid(url.param1);

versus 

if (isdefined("url.param1")) {
  if (len(url.param1)) {
    if (refind("[0-9]+", url.param1)) {
      doSomethingToValid(url.param1);
    }
  }
}

In the first case I can see all of the validation which will be applied in a list and I can get it all out of the way up front which lets me focus on the real substance of the routine. In the second case I have buried the substantial part of the routine deep in a nested section of ifs and when I need to add another rule to the validation that code structure just gets more complex.

Nick Van Brunt
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2

The two ways of writing it will return the same results, but for readability the first way is prefered

Robokop
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