hsmaxima

hsmaxima is simple module for binding Maxima CAS (Computer Algebra System) to Haskell programs.

No installation, just copy-paste the Maxima.hs to your working directory. No external libraries are required, Haskell Platform and maxima itself are only requirements.

Helloworld program looks like this:

{- maxhello.hs -}
import Maxima
 
--   Start maxima client on port 4424 and print answer for 2+2 expression
-- Though one can think, that there is maxima server, in fact Haskell script is server
-- and maxima itself is just client.
main = runMaxima 4424 $ \x -> askMaxima x "2+2" >>= print

The output is:

$ runhaskell maxhello.hs
["4"]
$ 

1. The output is returned as list. This is, because Maxima supports multiline scripts. You can make askMaxima x "2+2;sin(%pi/2);" and obtain two answers.
2. When error is occured, the output is ignored. So running askMaxima x "2+2;1/0;sin(%pi/2);" you will get only 2 results without information, which of three failed. To resolve this problems, you can run several askMaxima or use askMaximaRaw and parse result manually.

Feedback is welcome.

PS. One more example, interactive console:

import Maxima
 
maximaPrompt srv = do
    putStr "> "
    question <- getLine
    if question == ":q"
       then return ()
       else do answer <- askMaxima srv question
               print answer
               maximaPrompt srv
               
main = runMaxima 4424 maximaPrompt