Thease feature  will probably be present in ActionScript 4 .

• Generic Functions: This functionality will add Java-style method overloading to ActionScript. A function must be defined with the keyword generic, but then mutliple methods (with different method signatures) can be used.
• Iterators and Generators: Increased support for iterating over a series of values using a class defined iterator. Both of these items are very Python-like.
• Proper Tail Calls: A function can properly call another function as its last operation – this adds increased support for recursion patterns.
• New Number Types: byte, double, decimal (and the current generic ‘Number’ type would be removed)
• Numeric Suffixes: As in Java, numeric literals will have suffixes to denote their specific numeric type.
• Vector Type: As in Java, there will be a mono-typed array called Vector. Length can optionally be pre-defined at creation.
• Record Type: Describes the details of an object – easier to create than a class. I believe it is dynamic – in that it has required values, but additional properties can be defined per instance.
• Array Type: A type that describes what will be contained within an array. For example – you could say that you will have a 7-element array made up of Strings.
• Union Types: A property (or argument) could be one of a list of types (as opposed to now where a property has to be of one type – or no type). This would give you the ability to have an argument that could be a String or XML – but nothing else.