Dear fellow Haskellers and Haskellettes,
If you want to write Applets in Haskell there is no need to *compile*
Haskell to Java. A better option is probably to use Lambada, which gives you
a bidirectional interface between Haskell and Java. In other words with
Lambada you can call Java from Haskell *and* you can call Haskell from Java.
We (Sigbjorn Finne and I) have a paper that describes the implementation of
Lambada in all its gory details. We spend a couple pages to explain how to
make functions of type (a -> Object o -> IO b) an instance of the GoesToJava
class. Instances of this class can be marshalled from Haskell to Java. You
need this to implement event listeners in Applets and other GUI
applications.
We also have a preliminary implementation of Lambada, including support for
callbacks from Java to Haskell. The plan is to do a major revision once
STGHugs/DietHEP is stable enough. The differences to the user will be minor
however.
Martijn Schrage has implemented a nice generic XML editor
<http://www.cs.uu.nl/research/projects/proxima/> using Lambada where he
leverages on the AWT to do the GUI stuff.
If you are interested in a copy of the paper, or want to play with the
Lambada implementation, drop me a note.
Yours,
Erik Meijer
