Question

I have a class member in an ActionScript 3 class that looks something like this:

private var m_myvect :Vector.<MyType> = new <MyType>[];

I’m exposing it through a getter, like this:

public function get mydata() :Vector.<MyType>

Which doesn’t help when I use it like this:

for (var o:Object in inst.mydata)
{
    ...
}

… because the type of o is not MyType, but Number instead, because it enumerates the vector indices instead of the data.

How would I expose only the data within the vector in a way which:

• Allows me to use for(a in b) syntax
• Does not expose the data in a way which allows it to be modified?

Answer 1

for( var i:int = 0; i < mydata.length; i++ )
     // this will loop using the index - get your object using mydata[i] - it will be typed

for ( var o:Object (or String) in mydata )
     // this will loop through using the keys - it's more for looping through Objects and Dictionaries

for each( var type:MyType in mydata )
     // this will loop through using the values - what you're looking for

The only way to expose data that stops it from being modified (i.e. adding/removing items from the Vector, or changing the data in MyType) is to do it through functions on the parent object (that holds the Vector).

e.g.

public function changeSomething( index:int, item:* ):void
{
    // make sure the index is in bounds
    if( index < 0 || index >= this.m_myvect.length )
        return;
    this.m_myvect[i].whatever = item;
}