Simple IO Monad problem

Nick Name at
Sat Sep 13 01:25:39 EDT 2003

Alle 00:08, sabato 13 settembre 2003, kuq32tr02 at ha 
> ERROR "./mailalias.lhs":5 - Type error in final generator
> *** Term           : map putStrLn strs
> *** Type           : [IO ()]
> *** Does not match : IO a
> Can someone please explain what I'm doing wrong?

This is a type error. You have to "mapM_", not map, see the types in the 
documentation and try to convince yourself that you need an IO list and 
not a list of IO, then that you really need an IO () and not an IO list 
(wich would be returned by mapM). The syntax for a list of t in haskell 
is [t], in case you didn't notice.


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