StateT and WX gui coexistance

Question

Hello.

usual wxHaskell program looks like

main = do 
        run gui

gui = do 
    .... 
    ....

gui must have type IO a, run has type IO a -> IO (), also there is some initialization routines in run.

I'm tring to do following:

 data AppGlobals = AG { ... some data  ... }
 type MApp a = StateT AppGlobals IO a

But in this case gui must have type gui :: MApp AppGlobals. Due to it's type it becomes impossible to use usual IO monad syntax, I mean Ihave to use liftIO every time I performing IO action.

Is there Any convinient possibility to use State monad in wxHaskell? It's not very convinient to pass state to each event handler manually.

Answer 1

The wxHaskell programs I've read and written just shove the state into variables.
http://wxhaskell.sourceforge.net/doc/Graphics-UI-WX-Variable.html

Here's a good overview: http://legacy.cs.uu.nl/daan/download/papers/wxhaskell.pdf

And they use start rather than run.

Answer 2

It's possible in theory, but I've found it to be cumbersome in practice, as you did. My own wxHaskell code usually looks something like I described in the referenced blog article:

http://wewantarock.wordpress.com/2010/01/11/custom-controls-in-wxhaskell-part-3/

You can use wxHaskell variables, as ja suggested, for the same purpose, although I prefer the more explicit style I used in the blog.