[Haskell-cafe] HLIst - how to use TIPTransform with functions that run in the IO monad?

Andrew U. Frank frank at geoinfo.tuwien.ac.at
Thu Mar 25 17:34:45 EDT 2010

i use the TIPTransform module that Oleg has provided - very nice and easy to 
use! Thank you Oleg!!

now i run into a problem, i seem not to be able to resolve: how to use 
TIPTransform with functions that use the IO monad?

considering the example tip5 in Olegs communiation, where he uses a function 
with three arguments from the TIP (HList) and producing a result in the HList.

i would like to use a similar functionality, getting the arguments from the 
HList and producing a result which is again stored in the HList - but the 
function has a signature like f :: Int -> String -> IO String. the resulting 
string should go int the HList. i assume i need a function like ttip:
ttipM :: op -> db -> IO db?

can somebody help me with this? 
i appreciate any help!


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