ECMAScript 4 Netscape Proposal Introduction

Wednesday, September 4, 2002

• Motivation
• Notation

ECMAScript 4 is the next major step in the evolution of the ECMAScript language. ECMAScript 4 incorporates the following features in addition to those already found in ECMAScript 3:

• Class definition syntax, both static and dynamic
• Packages, including a namespace and versioning mechanism
• Types for program and interface documentation
• Invariant declarations such as const and final
• private, internal, public, and user-defined access controls
• Machine types such as int for more faithful communication with other programming languages

These facilities reinforce each other while remaining fairly small and simple. Unlike in Java, the philosophy behind them is to provide the minimal necessary facilities that other parties can use to write packages that specialize the language for particular domains rather than define these packages as part of the language core.

The versioning and access control mechanisms make the language is suitable for programming-in-the-large.

Waldemar Horwat Last modified Wednesday, September 4, 2002