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.

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Chapter 5: Operators

Nice, huh? Sometimes programming is so elegant. Such distinctive vertical lines...

such supple parentheses...

Logical Expressions and Data Values

Using logical operators to calculate a Boolean result is analogous to using arithmetic

operators to calculate a numeric result. For example, the following four operands

and three operators are used to calculate a single result:

(userStatus = = "registered") || (userStatus = = "specialGuest")

If the user is not registered, but is a special guest, this expression reduces to:

false || true

which in turn reduces to the Boolean result true.

Here is an analogous arithmetic operation that reduces to a single number:

(1 + 2) * (3 + 4) // Four values (1, 2, 3, 4), which become...

3 * 7 // two values (3, 7), which become...

21 // a single value (21)

Remember, a complex expression that reduces to a Boolean can be used anywhere

a single Boolean value is required (such as the test expression of a conditional

statement).

Logical OR

The logical OR operator is most commonly used to initiate some action when at least

one of two conditions is met. For example, “If I am hungry or I am thirsty, I’ll go to

the kitchen.” The symbol for logical OR is made using two vertical line characters

(

||). Typically, the | character is accessible using