flash language_api_execution_context

To avoid getting a nasty surprise it is worth spending a few moments on the new behaviour of reference functions.

As you probably remember, in ActionScript 1 and 2 we could pass a function in a reference, which then lost its original context and took on the new object as a context:

var person:Object = { age : 25, name : "Bobby" };
// the function to talk is passed as a reference
person.to talk = to talk;
function to talk ( )
{
trace(“hello, my name is “ + this.name + “, I am “ + this.age + “ years old�);
}
// call the method
// display: hello, my name is Bobby, I am 25 years old
person.to talk();

In ActionScript 3, the to talk function conserves its original context and doesn’t therefore execute anymore in the person object context:

var person:Object = { age : 25, name : "Bobby" };
// the function to talk is passed as a reference
person.to talk = to talk;
function to talk ( )
{
trace(“hello, my name is “ + this.name + “, I am “ + this.age + “ years old�);
}
// call the method
// display : hello, my name is undefined, I am undefined years old
person.to talk();

Many ActionScript developers use this change in context in order to reuse functions.We therefore need to bear in mind this new ActionScript behavior throughout all of these articles.