ECMAScript 4 again

A new pre-release of the reference implementation has been released. Head on over to the ECMAScript - Downloads site to get it. What are the changes? Well, taken directly out of Graydon’s announcement message to the ES4-discuss mailing list:

This release covers the cumulative set of fixes, enhancements, and adjustments to track spec discussions since October. Full details can be found in the bug tracker, but the summary entry in the HISTORY file follows:

Newly supported constructs:

• Super expressions


• Like types


• Wrappers (preliminary)


• Slice expressions


• __ES4__::Map.


• __ES4__::Vector.


• __ES4__::hashcode()


• __ES4__::DecimalContext, new decimal pragma


• uint32ops::*

Corrected behavior:

• Overhaul type system to conform to “valleyscript” model


• Strictness pragmas


• Cyclic type term prevention


• Type parameter scoping


• Property enumeration order


• Builtin prototype chains


• Builtin constructors


• Builtin conversions


• Builtin non-magic wrapper types


• Prototype property shadowing


• Scope rules for let expressions


• Arithmetic rules


• Function self-name binding


• Union types use “|” rather than “,”


• Regexp character class bug


• Hoisting bug


• Property-enumerability bug


• Nullability enforcement


• REPL error handling