TIP: Coding styles and $end errors

[tangoforce]

Hi

I'm sure many of you have come across the "Unexpected $end" or "Missing $end" messages many times and it's probably taken you many minutes, hours or even days to find it. If its the latter two options i'm sure if you're like me it's probably taken you a lot of desk thumping to to identify the fault.

Firstly I'd like to show you two different coding styles here:

PHP Code:

<?
//Example A - The most popular
function test_a($Input){
if ($Input){
print 'a';
}
}

//Example B - Less popular
function test_b($Input)
   {
   if ($Input)
      {
      print 'b';
      }
   }
?>

I've personally always found example B not only clearer to understand but easier to debug. Despite not fitting with the 'peer pressure' from other coders it is actually a lot nicer to work with and Notepad++ demonstrates this nicely too:



If you look at example A, you'll see that the opening brace is highlighted red along with its partner - Great huh?

Look at example B though and you'll see why it's so much easier to debug. Not only are the opening and closing braces highlighted red, NP++ also draws a red dotted line down the page directly to it so you can see it (Apologies, Photoshop didn't preserve the red dotted line very well). If you indent each block of braces as I have then it only makes things far easier to debug.

Following a recent thread by a member today I thought I would post this thread with a practical example in the hope that it helps others out here. The code has been slightly modified to remove the non-necessary html but it still serves as a good example for this demonstration:

PHP Code:

<?php
//This code will generate a missing $end error message
session_start();
require 'database.php';
$nuser=$_SESSION['user'];
$auser=$_SESSION['admin'];

if($nuser){
$userfinal=$nuser;
}elseif($auser){
$userfinal=$auser;
}
if(isset($userfinal)){
$Members = mysql_query("SELECT user FROM characters WHERE level ='1' ORDER BY exp DESC") or die(mysql_error());
$numRowsMembers = mysql_num_rows($Members);

for($count = 1; $count <= $numRowsMembers; $count++){
$name = mysql_fetch_array($Members);

echo "<a href=\"member_profile.php?username=$name[user]\"> $name[user]</a></td>";
}
?>

Now I'd like to show you this at work in Notepad++:
Style A:


Notice how the opening { are paired with the closing } in red circled with matching colours. The single { by itself is circled in red. Ok, by pointing at each opening { I've found the { without its partner - but where should I now put the closing } ?

The answer lies in Style B - using indentations and brackets on their own lines. Take a look at this:


Again, you can see all the correctly paired opening { and closing } in red circled with matching colours with the odd { circled in red.

Now due to the original authors code, there is no way of knowing if that for() block was supposed to be inside that block or outside of it. For demonstration purposes only, I'm going to show you what would of happened if it was supposed to be inside:


Did you notice that red dotted line circled in blue? - It shows you exactly where the closing } should be.

Now, lets look at the finished code:


Done, with ease. No time wasted, no head scratching, no convincing yourself there is no error with the code and the computer is wrong etc.

I hope that by posting this topic, some of you will see tha advantages that Style B has when used with a proper editor like Notepad++ and that it can actually help you to fix code rather than make it difficult like style A.

[Fou-Lu]

I'm quite a fan of this style with a minor variation: I set each brace aligned with the branch or control, and indent only where we exceed 80 chars on a line:

public int myMethod(<T extends Number> myIn)
        throws InvalidArgumentException
{  
}

for example.
I have NEVER been a fan of the braced single line, as its particularly difficult to identify braced and non-braced control blocks:

int c = 0;
for (int i = 0; i < 10; ++i)
    ++c;

// compared to
int c = 0;
for (int i = 0; i < 10; ++i) {
    ++c;

The only thing to note, is that many employers do have a particular code format style. So you must adhere to these styles. Fortunately, IDE's such as eclipse allow you to design multiple code templates, so when you are done with how you like to do it, you can apply a work style to reformat it if it uses the more common format.

This thread also deserves to be added to the PHP Frequenly Asked Questions thread.

Edit:
Sorry, can't quite recall the java syntax there for the exception. Its either InvalidArgumentException or IllegalArgumentException, but we shouldn't really get either in any case, it was just to show the indenting

[Fumigator]

Nice job on your tip. I used to use the first style but when I first started using CodeIgniter I switched to the second style. Mine's a bit different from yours-- I adopted CodeIgniter's style completely so my brackets are set on the same indent as the block identifier and all code inside the block is on its own indent. Notepad++ draws nice little dotted lines giving it a clean look.

[tangoforce]

Hi guys

Yeah I generally see the following two styles as being the same thing:

PHP Code:

function test_b()
    {

    }

function testb()
{

} 


I know it is technically different but the braces are still on their own lines so i see it as the same thing. I've always found it easier to understand though if they're indented from the function / class delcaration. I've never liked style A as its just too hard to understand, debug and most of all deal with $end errors. I have no idea what anyone likes about that style and why so many people use it. I can work with it, but i always end up copying the code from one notepad++ tab to another, formatting it my way, working on it, formatting it back and then pasting it back in.

Hopefully the screen shots in this thread will enlighten others