Comparison between JavaScript and ObjectScript

This is a comparison of Rhino JavaScript and ObjectScript. Since both languages offer a Java-like syntax and reasonable compiled performance, the details of the language will ultimately break the tie.

The solution in boldface is, in my opinion, the winner on that topic.

• Both have functions as first class objects and allow for true closures
• Both are dynamically typed
• ObjectScript provides lexically scoped variables, which is what we’re used to from Java, etc. JS provides variables that are either global or scoped within a function (they are not scoped within local statements)
• Both allow for polymorphic use of “+”: “Foo” + 3 = “Foo3”
• JS provides a syntax for using an expression to look up a property (field): x[s], where s is the expression. So, x[‘hello’] is equivalent to x.hello
• JS has a bunch of array handling functions: sort, splice, slice, concat, join, push, pop, shift, unshift. These are familiar to perl programmers and handy. ObjectScript does not mention these functions but does provide a convenience syntax for array slicing: var a = (1, 2.0, “c”); a[1..2] => (2.0, “c”). This syntax also works for strings, which is really nice.
• Both define objects as functions. JS provides a this variable to define the object that is being operated on. ObjectScript just assumes that you’re working with variables in the scope of your object.
• ObjectScript provides inheritance through an “extends” keyword, much like Java. JS uses a somewhat strange “prototype” construct. You set object.prototype equal to the function that you’re inheriting from, and that will be searched for any properties that are not defined within the object itself.
• Both provide straightforward mechanisms for extending Java classes

• JS with LiveConnect 3 automatically coverts Java Arrays and Strings to the JS equivalents. Example:

  s = new java.lang.String(“foo”)

  s = s + “”; // s is now a JS string

  s.match(“oo”)

• JS is well-documented in books, because it is widely used. Most books, however, cover JavaScript usage in web browsers. However, the language itself is well-covered because it is a standard. There are formal language definitions and some articles that cover the language design

The proposed JavaScript 2.0 language aims to provide greater power for creating large applications with JavaScript and better interoperability with Java. It adds a more disciplined class syntax with versioning, a package system, optional types and type-checking, conditional compilation and access controls. JS 2.0 adds a strict mode which adds a few rules that are not onerous but clean up the language a bit (and adds lexical scoping, instead of the odd function scoping that exists in JS1.5).

Conclusion

ObjectScript and JavaScript have very similar language features. I would give the win to JavaScript for its easy hashtable (associative array) syntax, and useful collection of array functions. Rhino JavaScript (ECMAScript) is a commonly-used, well-supported, well-documented tool. The JavaScript 2.0 future offers some nice features. Plus, the ability to use the same language on the server side that we may use on the browser is a plus. Add decent performance to all of this, and you end up with JavaScript being a solid choice.