Datasheet

Chapter 1: A Quick Introduction to Programming

❑ Are you writing a block of code that you think you might need again in some other part of the

script, or in another script? Move it to its own procedure.

❑ Are you writing some code that you think someone else might find useful? Move it.

This isn’t a science and there are no hard and fast rules for code — after all, only you know what you

want it to do. Only you know if parts are going to be reused later. Only you know how complex

something will turn out. However, always keep an eye out for possible modularization.

Use the “Hungarian” Variable Naming Convention

You might hear programmers (especially C++ programmers) mention this quite a bit. While this is a bit

out of scope of this introductory discussion, it is still worth mentioning nonetheless. The Hungarian

naming convention involves giving variable names a prefix that indicates what the scope and data type

of the variable are intended to be. So as not to confuse matters, the Hungarian convention was not used

in this chapter, but you will find that most programmers prefer this convention. Properly used, it makes

your programs much clearer and easier to write and read.

See Chapter 3 for more on Hungarian notation variable prefixes. The standard prefixes for scope and

data types are in Appendix B .

Don’t Use One Variable for More Than One Job

This is a big no-no and a common mistake of both beginner and experienced programmers alike (but the

fact that experienced programmers might have a bad habit does not make it any less bad). Each variable

in your script should have just one purpose.

It might be very tempting to just declare a bunch of generic variables with fuzzy names at the beginning

of your script, and then use them for multiple purposes throughout your script — but don’t do it. This is

one of the best ways to introduce very strange, hard to track down bugs into your scripts. Giving a vari-

able a good name that clearly defines its purpose will help prevent you from using it for multiple pur-

poses. The moral here is that while reusing variables might seem like a total timesaver, it isn’t and can

lead to hours of frustration and wasted time looking for the problem.

Always Lay Out Your Code Properly

Always remember that good code layout adds greatly to readability later. Don’t be tempted to save time

early on by writing messy, hard to follow code because as sure as day turns to night, you will suffer if

you do.

Without reading a single word, you should be able to look at the indentations of the lines to see which

ones are subordinate to others. Keep related code together by keeping them on consecutive lines. Also,

don’t be frightened of white space in your code. Separate blocks of unrelated code by putting a blank

line between them. Even though the script engine will let you, avoid putting multiple statements on the

same line. Also, remember to use the line continuation character (

_ ) to break long lines into multiple

shorter lines.

The importance of a clean layout that visually suggests the logic of the underlying code cannot be

overemphasized.

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