What to make into functions

mbaldwin577

Hi,
I have been signed up here for a while, but forgot I was. I hope to get a little assistance though. I would consider myself an advanced beginner of php. I know enough to get myself in trouble, but I do not know as much as I want to know. I have decided to work on a personal project to gain experience and learn a lot more, and eventually work as a free lance php developer, or work as an intern for a developer. Anyways none of that matters to much.

How do you decide what to make functions for and what not to make them for? I am working on a signup script that has 15 fields to be checked. A couple of the fields, like first name and last name I am using the
same checks for, and other stuff like email and password will be used again in the login form. Does it make more sense to put all these in like a form.validate.php file, and include that file and use the functions where needed? Or is this where I should learn more about classes and such? I do all writing procedurally. I can post a sample of the signup script if needed, but no laughing at it.

I am sure there is something out there I can use already, but I won't get experience if I don't do it. I use nothing fancy, in fact I write all my code by hand in notepad. I am not interested in a framework, or template engines. I like to know exactly what is going on before using stuff to make life simpler.

Thanks,
Michael

NogDog

The first flag for me usually as to whether something belongs in a function is if you find your self writing the same code (or practically the same code) in two or more places. If you copy-and-paste code from one place to another, that's probably a strong signal it could be in a function. By avoiding duplication, you only need to get it "right" in one place, and if the logic/specifics need to change, you only need to change them in one place.

A second reason is to isolate sections of complexity so as to keep the main flow of logic clear and readable. This may not have quite as much impact on your application's robustness as the avoiding-duplication reason, but can be a benefit downstream when debugging/updating the code.

mbaldwin577

thanks, that is what I was kind of leaning towards, but wasn't quite sure.

Can i put my functions here to get some thoughts on it, or is that better in the code forum?

Thanks,
Michael

NogDog

mbaldwin577;11012903 wrote:
thanks, that is what I was kind of leaning towards, but wasn't quite sure.

Can i put my functions here to get some thoughts on it, or is that better in the code forum?

Thanks,
Michael

Either is fine. Responders tend to cut posters a bit more slack when they post in the Newbies forum -- though overall it's a friendly place anyway (unlike some tech forums where members like to put n00bs down). You may be a bit more likely to get more eyes on it in the General or Coding forum, though. Just don't cross-post the same thing in 2 or more sub-forums, in which case we won't cut you any slack. 😉

Weedpacket

One rule of thumb I've heard - basically NogDog's second reason - is, if you find yourself tempted to write a comment explaining what a block of code does, then that block of code is a candidate for being made into a function (with a name that explains what it does).

When I first started my formal programming education, I was taught pseudocode and flowcharting (yes, it was a long time ago). A quick search finds me this. It's somewhat similar; the most visible difference being that my use of pseudocode was combined with the previous paragraph, so the comments would be replaced by the corresponding code, which itself would be just as self-explanatory:

// return the container
  return $webPages;

No! really!?

mbaldwin577

Thanks,
I got it done and it seems to work now. It did not really seem to save me any lines of code, but at least now the form validations are in a different file, and there is only one place to update a preg_match() instead of 3 or 4. I will post the code in the codes forum to see if I am on the right track. I got to go add comments first. I am one of those bad people who doesn't comment.

Thanks,
Michael

NogDog

mbaldwin577;11012943 wrote:
Thanks,
I got it done and it seems to work now. It did not really seem to save me any lines of code, but at least now the form validations are in a different file, and there is only one place to update a preg_match() instead of 3 or 4. I will post the code in the codes forum to see if I am on the right track. I got to go add comments first. I am one of those bad people who doesn't comment.

Thanks,
Michael

As the Weed-man suggested, really well written code may not need much in the way of comments, if function and variable names are descriptive enough. By all means, though, stick them in where you think it's not obvious what or why you are doing something, but if you feel some part of the code really needs a comment, it may be a sign that it could be better written (or that you are under schedule pressure, like most of us. 🙂 )

Bonesnap

mbaldwin577;11012943 wrote:
It did not really seem to save me any lines of code...

Don't fall into the trap of fewer lines means better or more efficient code. There is a balance between efficient/concise code and readability/maintainability (determined by you). You might be able to compact four lines into one but the statement itself might look ridiculous and require some comments, which defeats the purpose.

Also, there is an additional advantage to putting code into functions: external reusability. What I mean by that is now you can use these functions in other projects and, if you develop these functions enough, you could even create an API out of them.