Macromedia’s Gary Grossman, Architect for the Flash Player started off with a history of the evolution of Flash’s
scripting language.
Why develop ActionScript 3.0? Performance. Tighter
structure. Previous choices in AS development may not have
been optimal and may have become debugging challenges.
Silent failure of too many errors. Incomplete repair of
these issues in AS2.
Many significant changes in AS3. It will be challenging to
port existing apps. VM and other major changes shouldn’t
make any difference in development. It will provide a solid
platform for the future of the Flash Player.
AVM2 (the new virtual machine) only executes newly-compiled AS3-compatible files. Both VMs will be kept in the Player. Entirely new bytecode instruction set, will be under 1MB. Codenamed “Zaphod” (which I think Gary pronounced “zaffud,” but which should be “ZA-fod”).
AS3 includes native classes, string types, access specifiers, namespaces, error reporting, optional parameters and rest arguments, method closures, regular expressions, EX4 (EMAScript for XML), full standards compliance.
Gary went into a fair amount of detail about each of the major changes to ActionScript, but I’m not able to pay enough attention to know what he was talking about and take notes simultaneously.
One item, rest arguments, allows for functions with an open-ended number of arguments. Capitalization nazis will love AS3!
Loooong day. Long week. Ready to go home.