[Haskell-cafe] Building GUIs for Haskell programs

[Jules Bean]

On 12 Jan 2005, at 11:10, Matthew Roberts wrote:

>> Can anyone attest to the sense (or otherwise) of the following 
>> programming "pattern"
>>
>> - program all back end stuff in Haskell and compile to library
>> - program all GUI stuff in *insert imperative language of choice" and 
>> link to the library for back end functionality
>>
>> It seems the ultimate decoupling of interface from logic.
>>

This is roughly how I handled a recent project, in a mixture of ML and 
Java.

Frankly I regret it: if I did it again, I would do the whole thing in 
ML (or perhaps haskell).  Once you get used to languages with real 
higher-order features and powerful abstraction notions, it is a real 
pain reverting to a language like Java (or C or C++ or perl or...)

ML, despite being thought of as a primarily functional language, is 
still (IMO, of course) a 'better' imperative language than Java, 
because of features like closures and local declaration of functions. I 
think the same holds of haskell using an appropriate monad instead of 
ML's imperative features.

All this is of course entirely dependent on having a suitable GUI 
library or set of bindings for haskell. I haven't tried wxHaskell yet 
so I can't comment there. (And for some applications, some languages 
may be too slow, but I was ignoring efficiency in the above)

Jules