On Sat, 27 Nov 2004 19:30:20 -0500, Sam Ruby <[EMAIL PROTECTED]> wrote: > Probably the best base to start with is Rhino, which is a standalone open > source JavaScript compiler written in Java - originally done by the > JavaScript team at NetScape. This code is quite good. And coincidentally is > in the process of absorbing a set of patches to add continuation support.
Actually, I've spent the last couple of hours looking into three implementations: Narcissus, Rhino and SpiderMonkey (and SEE a little, too). I'd say Narcissus seems like a far better starting point for at least two things: First of all, it's a JavaScript in JavaScript implementation. Second, it's by far the easiest to get a grip of. (Probably because of what language it's written in. C and Java contains so much syntactic sugar...) The bad part is that Narcissus is an interpreter and not a bytecode compiler, unlike the other two. As for continuations, I've known about Cocoon for a while, and their Rhino with proper tail recursion and first class continuations. It's neat, and I'd certainly not go any other way. (Parrot should make this easy, compared to JVM/CLR...) > Overall, JavaScript would be a good match for Parrot. One place where it > would significantly diverge at the moment is in the concept of a "class". > Objects in JavaScript are little more than bundles of properites, some of > which may be functions. And classes are essentially templates for such > objects. I don't really think it's that strange. Essentially, all objects contain a reference to their prototype. When getting a member of an object, the object will first check it's own members for the corresponding identifier, then ask it's prototype, and so on until the prototype chain is depleted. Setting is always done on the object itself. It's really not so much inheritance as it is conditional runtime delegation. Functions are of course first class and shouldn't differ from any other member - there is no native method/property distinction in JavaScript, even though host object may have such a distinction. The difference between a function and a method is the binding of the this keyword. Privacy is all handled by the closure creation, so that should be a freebie with implementing constructors. Note that the prototype delegation system could very well exist on an object which inherits properties from a class, if the host allowed it. The systems are orthogonal. But then I expect that to get ugly fast, especdially with a Ruby-like class system... Hopefully LiveConnect can be tweaked so that it can give the same automatic wrapping/unwrapping of parrot native objects as it provides for Rhino and Java natives in JVM. -- David "liorean" Andersson <uri:http://liorean.web-graphics.com/>
