Statements (ActionScript: The Definitive Guide)

Chapter 6. Statements

To make something happen in Flash -- whether stopping a sound, playing a movie, running a function, or looping some code -- we use a statement. In fact, an ActionScript program can be defined as nothing more than a list of statements that tell the interpreter what we want Flash to do. Here, for example, is an entire ActionScript program, which consists of four statements and tells the interpreter to load a web page into the browser:

var protocol = "http";                                   // Statement 1
var domain = "www.moock.org";                            // Statement 2
var path = "webdesign/flash/";                           // Statement 3
getURL(protocol + "://" + domain + "/" + path);          // Statement 4

Scripting a movie with ActionScript is simply a matter of attaching statements to frames, movie clips, and buttons. This chapter explores the syntactic makeup of statements and lists the general statement categories. We'll touch on all the ActionScript statements in this chapter, but some of the more important ones will be examined in detail in later chapters.

6.1. Types of Statements

Conceptually speaking, there are five core types of statements:

Statements that control the execution flow of a program: loops

conditionals

ifFrameLoaded
Statements that declare variables: var

set
Statements that declare, call, and return values from functions: function

function call

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 to 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 thousands of things we can do via function calls. First, let's see how statements are formed.

Chapter 6. Statements

Contents:

6.1. Types of Statements