On Wed, Oct 27, 2010 at 7:46 PM, Martijn Schrage
On 27-10-10 16:20, Victor Nazarov wrote:
Very cool. I'll incorporate your changes, If you don't mind.
Not at all.
However, I have some minor remarks. You shouldn't override hscall function, or you may break partial application implementation. And you shouldn't overide properties of evalFn, I wonder that this doesn't break your example...
Ah, yes, that was the guessing part. I just hacked around a bit and thought I'd leave the correct definition to someone who actually knows what they're doing :-)
var evalFn = new $hs.Func(1); evalFn.evaluate(arg) = function(arg) { var argStr = $hs.fromHaskellString(arg); var res = eval(argStr); return $hs.toHaskellString(arg); // This function should be added to $hs object/namespace }
This works without any problems (after changing the second line to: "evalFn.evaluate = function(arg) {")
I think we should do something like this:
data JsObject = ... -- Should be made abstract
and
eval :: String -> [JsObject] -> JS JsObject
So we can pass around javascript-objects in haskell program and bind them back into javascript calls. And use some conversion functions in case when we need data:
jsObjectToString :: JsObject -> JS String jsObjectToInt :: JsObject -> JS Int
Yes, that seems logical. The JsObjects can then be treated similar to IORefs.
What are your plans with the package? In my opinion, this work could be extremely useful for building Ajax apps, and it doesn't seem to be that far from being usable already.
Some interesting near-future work I can think of:
- Make it work on all major browsers This shouldn't be a problem...
- A faster and more robust module loader (now it loses a lot of time on 404 errors, trying to access modules in the wrong package dir) I agree that this is important. I'll look into it...
- Basic type checking for the top-level Haskell functions I think this should be implemented via FFI export implementation.
- Marshaling between Haskell and JavaScript values Again It's mostly implementation of Haskell FFI
- JQuery support - Nice ways to build JavaScript (and JQuery) expressions in Haskell Dmitry Golubovski had a code generator from WebIDL wich he used to support HTML5 DOM in YHC.
- Support more libraries and packages (Parsec would be interesting)
I think Parsec should work right now out of the box. But I don't have time to investigate it...
I can find some spare time to work on this. I'm sure there will be others as well.
I want to make code generator more smart and generate more optimized code. To archive this I need to rewrite it in Monad or ApplicativeFunctor style. I need Reader monad there to pass some environment. I think ghc-packages support is rather trivial to add. So module loader will always know the one true location of module. I want to implement continuation passing style calling convention for Haskell-values as an alternative to two existing ones: plain and trampoline. This will even allow multithreading emulation (with setTimer as a scheduling mechanism...) And last, I want to dig into FFI implementation. I think GHC doesn't allow extensible FFI. So you won't be able to write "javascript" calling convention in Haskell source file. But I think we can overcome this using "ccall" for example... I don't know what tasks are of most priority. I do what I feel like doing :) I'll be very interested to see what other people can do with all this. And I think that we should switch to application driven development some time with something like Yampa-based game running in web-browser... -- Victor Nazarov