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.

Statement Syntax

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Statements that declare variables

var

set

Statements that declare, call, and return values from functions

function

function call

return

Statements that deal with objects

with

for . . . in

Statements that represent a data value

any expression (especially expressions with side effects)

These informal categories help us understand what we can tell the interpreter to do

using statements. At first glance, the list may seem fairly limited. However, we’ll see

that there are many variations of conditionals and loops and that there are thou-

sands of things we can do with function calls. First, let’s see how statements are

formed.

Statement Syntax

Statements are typically made up of keywords and expressions. We’ve already seen

the var statement, which declares, and optionally, initializes a variable. Here’s an

example of the var statement’s general syntax:

var numFrames;

The keyword (var in this case) begins the statement. Each keyword is followed by the

syntax (parentheses, parameters, operands, etc.) required to complete the statement,

which, in our example, is simply the name of a variable,

numFrames. Finally, a semico-

lon marks the end of the statement.

In ActionScript, every statement should end with a semicolon, which

is not to say that there is one semicolon per line of the