It happens to everyone. You’re typing hundreds and thousands of lines of code, and you suddenly find yourself stuck. You need to come up with the name of a new variable, and you can’t find one. It’s something so incredibly easy, yet you can’t think of a name for it.
That’s because deep down, you _know_ it’s not easy. You know this variable will come back to haunt you weeks later when you’re maintaining the code, and forgot what data it held. While there’s nothing as easy as naming all variables $a, $b, $c, … it just doesn’t cut it in the long term.
Let’s kick it off with some wrongfully named variable examples. Don’t use overly descriptive words in variable names. While the content of the variable may change, the variable’s name usually doesn’t. Take the following CSS snippet.
.left_content_green {
color: green;
padding: 5px;
}While this might seem like a good idea, it’s really not. Since CSS is ment as a way to manage your site’s layout & mark-up in a centralized place, changing styles, content, … is a piece-of-cake through a couple of CSS files. But naming your class “left_content_green” will make it horribly complicated to maintain once you decide to change its color to red. You’re only supposed to change it in the CSS, not change the class name inside your project. Now your class called “left_content_green” is causing your content to turn red.
Be clear. While it may sound simple, clean and easy variable names apparently don’t come easy. Consider the following two pieces of code. Both perform the same action, yet one of them is remarkably easier to read & manage .
while (!$notRunning) {
// Do something, until completed
}
while ($running) {
// Do something, until completed
}The first while-loop can cause confusion. A double negative (“while not NotRunning, do this”) will add complexity where it’s not needed. The second loop, stating “while running, do this” is both easier to understand, and to write.
Keep your variable name, datatype & content aligned. This mostly holds true for loosely defined languages, such as PHP, where you can change the datatype of a variable on-the-fly, without problems. Just don’t do this, for _whatever_ reason there might be (and I’ve seen this happen all too often).
// Start the script
$intStartingNumber = 5;
for ($i = 0; $i < $intStartingNumber; $i++) {
echo $i;
}
// Add 15k+ lines of code ...
// Hey look, a variable $intStartingNumber that we haven't used in a while
$intStartingNumber = "five";
for ($j = 0; $j < 5; $j++) {
echo $intStartingNumber;
}If you don’t recognise the scenario above, consider yourself lucky. It’s a common mistake found in almost every PHP script. If you reuse your variable (which is fine – don’t get me wrong), make sure the variable is atleast still named properly.
Matti PHP convention, naming, PHP, variables
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