Web Site Cookbook

2.6. Establishing a Naming Convention for Your Variables

Problem

You need to follow a dependable pattern for naming variables in your web site scripts.

Solution

Develop coding guidelines that make sense to you, your team, and your web site, and then stick to them.

In general, a good variable naming scheme:

• Uses unique, concise terms

• Limits abbreviations

• Avoids reserved words in its programming language

• Serves as a form of self-documentation

Discussion

Variables are used to store alphanumeric values that will be manipulated by a script or program. Variables can have a constant value defined permanently in the code, or be changed from one value to another through logic or input from a user.

For example, a PHP script might take a Fahrenheit temperature value entered on a web site form (call it $temp), perform a calculation on the variable to convert it to Celsius, and then echo the same variable (with a new value) back to the user.

The variable name $temp has several disadvantages (that's why I chose it). As a generic abbreviation for temperature, $temp easily could be misconstrued as representing a temporary value (or the user's temperament) by another programmer reviewing the code.

Tip

If you find that you have to use abbreviations or shorthand for your variables, compile a glossary and add it to a central comment block in your script.

While the name $temp meets the simple needs for a hypothetical temperature converter, it becomes woefully inadequate as soon as you try to add other functionality ...