[Resolved] General coding question (parsing efficiency?)

davidjam

Best way to explain:

function func() {
          if($var) {
                    .. result ..
          } else {
                    .. a whole lot of code ..
          }
}

function func() {
          if($var) {
                    .. result ..
                    return(); <<<----
          } else {
                    .. a whole lot of code ..
          }
}

Is the latter necessarily faster for PHP to parse than the former or does it not make what bit of difference? I'm just a beginner to PHP so I want to have good coding practice... 🙂

Roger_Ramjet

Using Return is always the way to go. Control is passed back to the calling routine as soon as return is encountered. Much more efficient. Although in your example it would not actually make much difference since it's an if-else. In other cases it would. Being explicit in your code execution paths is also good software enginering practice. So

function func($var) {
          if($var) {
                    .. result ..
                    return $result;
          } else {
                    .. a whole lot of code ..
                    return $other_result;
          }
}

// is 'better' than 

function func($var) {
          if($var) {
                    .. result ..
                    $foo = $bar;
          } else {
                    .. a whole lot of code ..
                    $foo = 'lamb';
          }
return $foo
}

// or the even worse

function func($var) {
          if($var) {
                    .. result ..
                    $_SESSION['foo'] = $bar;
          } else {
                    .. a whole lot of code ..
                    $_SESSION['foo'] = 'lamb';
          }
}

davidjam

Originally posted by Roger Ramjet
.. Although in your example it would not actually make much difference since it's an if-else. In other cases it would. Being explicit in your code execution paths is also good software enginering practice.

I guess that is what I was wondering, whether it makes any difference, but I also agree with you about good coding practice. For one thing it makes reading the script easier because you don't have to search down the page to see if there will be anything else after the return()

Code by roger ramjet

// ...
// or the even worse

function func($var) {
          if($var) {
                    .. result ..
                    $_SESSION['foo'] = $bar;
          } else {
                    .. a whole lot of code ..
                    $_SESSION['foo'] = 'lamb';
          }
}

Why do you say this is a problem?

Installer

Because it makes the function almost totally non-reuseable, for one thing.

[edited for spelling]

Roger_Ramjet

Yes. And also because it sets an external variable instead of returning a value, which technically means it is not really a function anyway. But the side-step of returning the result by pre-emptively setting a session var, which could tempt you with it's processing efficiency, means that you have to read the function code to find out what is happening every time it is called. Pain in the ass to maintain for someone and bound to cause bugs.

davidjam

Sorry, I didn't actually read your code carefully. Your bad, better and best examples were really clear,... that is, once I took the cucumber from my eyes (and the brocolli from my ears, the carrots out of my nose...).

Thanks alot! 🙂