The following program prints Right ("test","Bool","True") as it should, but it leaves behind in /tmp two files (name is a long string of digits) and an empty directory (name is ghcNNNNN_N). ... and it deletes the input file (/tmp/Main.hs). That's not nice. Ideally, I would want to read input from a String (instead of the file), and not write to disk at all. But cleaning up properly would be OK as a work-around. import Language.Haskell.Interpreter import Mueval.Interpreter import Mueval.ArgsParse main = do writeFile "/tmp/Main.hs" "test = True" result <- runInterpreter $ interpreter $ Options { timeLimit =1, modules =Just ["Prelude"], expression ="test" , loadFile ="/tmp/Main.hs", user="what", printType =True , extensions =False,namedExtensions = [] , noImports =False, rLimits =False, help=True } print result ghc --version The Glorious Glasgow Haskell Compilation System, version 7.4.1 ghc-pkg list| egrep 'mueval|hint' hint-0.3.3.4 mueval-0.8.1.1 uname -a Linux octopus 3.0.0-16-generic #29-Ubuntu SMP Tue Feb 14 12:48:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux