We want to change the grip JS has on the DOM and on XUL. We will do this in 2 steps:
Ideally, the first step could be done without consideration for the second, in the assumption at the implementation should be truly language neutral.
But regardless of scripting language, there is the fact that XForms is out there looking to take on the very need for scripting in many of the browser use cases. Kurt says:
I am a major advocate of XML, precisely because it is much more difficult to isolate a language when a mapping is essentially an XSLT transformation away. For this reason, XForms is a very attractive model to be moving towards, certainly, and I look forward to the day that I can build XForms applications that work in all browsers equally. However, XForms is not even remotely widely implemented yet nor are there standard forms of declarative binding languages along the lines of XBL (sXBL is getting there, but so far there are perhaps two still very much test implementations in existence).
Chime predictably takes exception to this (in a response to Kurt). He's been a very involved early adopter of XForms, and I've been amazed to see how productive XForms has made him, so I take his point very seriously when he says:
I beg to differ. Though it may be true that it doesn't quite have the traction that Flash has at the moment, I wouldn't go as far as saying it isn't remotely, widely implemented. There are several very mature implementations...
To be fair, I think Kurt was saying that script is only needed for the 20% case, and not the 80% case. He just felt that declarative solutions architecture "is hideously inappropriate for the remaining 20%." I do agree with that, but I think that people (not Kurt) tend to exaggerate this fact as an argument against declarative programming.
Chime wraps up:
I must give the disclaimer that I'm not suggesting XForms will be a user interface / browser-based application building [panacea], but rather that the potential it has to eliminate the unportable, architecturally unsound code that often drive DHTML web-sites with minimal complexity is very much overlooked.
Based on what I've seen of XForms, I tend to agree. I actually think Chime and Kurt are more in agreement than they sound, except maybe on the matter of the maturity of XForms engines.
At almost the same time another script versus XML exchange was going on in Mark Birbeck's blog, and in particular "On Adobe and XForms via Declarative Programming, Wizards and Aspects". That article is well worth reading in its entirety, but I'll highlight what he says about Wizards:
...in nearly all cases I find the 'wizard approach' is great to get you started, but then very quickly gets complex again. Anyone who uses Microsoft's Visual Studio, for example, will know that getting a C++ application up and running quickly, with support for multiple windows, toolbars, printing and file saving, is a snip. But then when you want to modify that code and move away from the wizard, you are very soon into normal C++ territory.
I tend to put this point even more strongly, as I do in my article "The worry about program wizards", but I'm always happy to have it reinforced.
In some ways I see wizards as the shoddy high street knock-off of declarative systems. Well designed declarative systems fully encapsulate modal aspects of the application in development, and they expose slots for ready extension in imperative implementation, if needed. Wizards, on the other hand, do focus on parameters in a way tantalizingly like declarative systems, but then ruin the entire plot by handing the programmer a hairball of imperative code that they have to hack at arbitrarily in order to complete the application. It's the difference between just plugging a device into a USB port to add capability to your PC, rather than having the motherboard thrust in your face so that you can find the right place to solder in the leads.