Functions

Functions in AS 3.0

Functions are reusable blocks of code stored under a name, that are easy to be called back in Action Scripting.
The first time you introduce a function in a piece of code, you need to DECLARE the new function, including: the word function, the name of the function, the parenthesis (that holds the event ype or the parameters) and the data type.

function
 goStep2 (Event:MouseEvent) : void {
function
 name event type data type {
gotoAndPlay
 ("part 2") }
method
 parameter close

 

A more complex function, of a differnt type and with parameters would look like this:
(notice that the parameters are variables)

function
 myFunction ( myNumber:Number , myString:String ) :Boolean {
function
 name ( parameter , parameter ) data type {
if
( myNumber == 7 ) return true ;
conditional
 ( parameter operator numb )   ;
if
( myString . length ) return true ;
conditional
 ( parameter dot property )   ;
return false ;
boolean return
  

Case specific: function to detect keyboard input

Detecting keyboard input relies on 2 keyboard events: KEY_UP and KEY_DOWN.
When the user presses down on a key the KEY_DOWN message is sent. You need to set up a listener to track it down. The listener will be link to the Stage as an object.

stage.addEventListener (keyboardEvent.KEY_DOWN, keyDownFunction)

function keyDownFunction (event:keyboardEvent) {
if (event.charCode == 32){
spacebarPressed = true;
}
}

Properties of keyboardEvents

charCode, that returns the character number of the keypressed, and is affected by the Shift key.
keyCode returns the character number of the keypressed but it is not sensitive to shift.
ctrlkey, shiftKey, altKey representing whether those modified keys are pressed.