Subj : Re: Creating classes/namespaces on the fly from existing functions?
To   : netscape.public.mozilla.jseng
From : Shanti Rao
Date : Wed Jan 12 2005 10:41 am

Bubbfree brings up the idea of a system that loads source code from a 
database, rather than from souce code. IBM VisualAge did something like that, 
and JS2's package system seems to anticipate the desire.

I suspect that several people on this list are designing development 
environments to do just that, and that's why we see so many requests for 
source code validation from SpiderMonkey.

One of VisualAge's features was the ability for you to edit a function, but 
for your changes not to affect anyone else until your code had successfully 
compiled and passed a few tests. Version numbers were tracked for each 
function, and you could compile a binary with any combination of functions of 
different ages.

Since the SpiderMonkey APIs are so easy to use, you can do a lot of that with 
JS1.5, only using functions instead of directives. The import directive 
becomes an import function, the package directive is unnecessary, and objects 
are a substitute for namespaces. (A threading system isn't necessary, but it's 
really useful, so embedders frequently make one.)

I mention this because, there's a great diversity among the JS 
implementations. Code written for jsolait's object model will be unlikely to 
run on JSDB. A Synchro.net module wouldn't load into egachine. Code written 
for XPCOM is tied pretty strongly to XPCOM.

That's not necessarily bad, since the people who use these projects probably 
are unaware of each others' existance. And having many different SM embeddings 
is a way to apply natural selection to the language development. Consider, for 
example, the various networking implementations. Is it better to have bindings 
for socket functions or to have an abstract stream object? Or files. Would you 
rather have a File.open() function or a new File() object?

So, all you embedders out there, what kind of source-code-management system 
are you hoping to add to your JS system?

1. File-based packages like Perl
2. Hierarchical file-based-packages like Java and the JS2 spec
3. Function-level versions like VisualAge
4. Files without packages
5. Files with namespaces
6. Other?

Shanti

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