ActionScript for Flash MX: The Definitive Guide, Second Edition

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

Some Basic Phrases

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9

Perhaps not as friendly as saying hi, but it illustrates one of the true foundations of

programming: Flash can remember something for you, provided that you label it so

that it can be found later. For example, in your second line of code, we had Flash

remember your first name, and we named the reference to it

firstName. Flash remem-

bered your name and displayed it in the Output window, due to the trace() com-

mand, when you tested your movie.

The fact that Flash can remember things for us is crucial in programming. Flash can

remember any type of data, including text (such as your name), numbers (such as

3.14159), and more complex kinds of information that we’ll discuss later.

Official variable nomenclature

It’s time for a few formal terms to describe how Flash remembers things. So far, you

know that Flash remembers data. An individual piece of data is known as a datum.A

datum (e.g., “Hi there, Flash!”) and the label that identifies it (e.g.,

message) are

together known as a variable. A variable’s label is called its name, and a variable’s

datum is called its value. We say that the variable stores or contains its value. Note

that “Hi there, Flash!” is surrounded by double quotation marks (quotes) to indicate

that it is a string of text, not a number or some other kind ...