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Netscape’s proposal

When Netscape submitted its proposal to TC39, the future of Netscape Communications looked bleak.

Since that time, Netscape was purchased by Time Warner (then AOL Time Warner) and then summarily

disbanded, leaving the future of its Web browser strictly to the open-source Mozilla Foundation. The

Mozilla Foundation still supports the Netscape proposal (which can be viewed at

http://www.mozilla

.org/js/language/es4/

) and updates it periodically, although the last update noted was in June 2003.

Netscape’s proposal for ECMAScript would turn ECMAScript into a lightweight version of the Java pro-

gramming language. The goals listed in the proposal are the following:

Making the language suitable for writing modular and object-oriented applications

Making it possible and easy to write robust and secure applications

Improving upon ECMAScript’s facilities for interfacing with a variety of other languages and

environments

Improving ECMAScript’s suitability for writing applications for which performance matters

Simplifying the language where possible

Keeping the language implementation compact and flexible

Although these goals seem pretty ambitious, the proposal is quick to point out that its authors do not see

ECMAScript as a replacement for C++ or Java, nor do they intend to push it in that direction.

In order to accomplish the goals listed previously, the Netscape proposal suggests a number of changes

to the language from the third edition. These changes include:

Optional strict typing and type checking of values.

As discussed throughout this book,

ECMAScript is currently a loosely typed language. The proposal asks to change this in order to

cut down on errors and bring ECMAScript more in line with other object-oriented languages.

More logical syntax for classes.

In the current edition of ECMAScript, a strict difference exists

between defining a global function and defining a class. This proposal suggests the use of the

reserved word

class

to make the syntax for defining classes more logical (and ultimately, more

Java-like). This would include using the

extends

reserved word for more straightforward

inheritance and the introduction of private and protected scopes.

Addition of more types.

Because one of the main goals of the proposal is to allow for easier

interaction with other languages, it is suggested that the fourth edition of ECMAScript include

more types, such as integer and long, that are supported in other languages.

Keywords and reserved words

Netscape proposes the following keywords:

break

case

catch class

const

continue

default delete

else export extends false

finally for

function if

import in

instanceof

namespace new

null package private public

return super

switch

this throw

true

try

typeof use

var

void while

with

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Chapter 20

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