Self invoking functions in ActionScript 3

Consider this normal example:

function greetings():void 
{
    trace( "Hello World" );
}
greetings();

This will display "Hello World".

The above example can be written in more elegant way (i.e., self invoking the function) as:

(function greetings():void {
    trace( "Hello World" );
})();

You get the same result. It's a function expression. Function expression syntax is of the form:

( f )();

Another example:

(function greetUser( name:String ):void {
    trace( "Hello " + name );
})("Awesome");

You pass an argument during self invocation.

However one important thing you must consider is the scope.

(function greetUser( name:String ):void {
    trace( "Hello " + name );
})("Awesome");

greetUser( "Foo" );  //will result in error

So note that.