Hi there, I thought i can reverse a list with reverse a list easily with the reverse function in order to achieve following: I wanted to check for a certain suffix (then reversed a prefix) and substitute that. So i did -- let dstfile = case tmpfile of -- ('a':'s':'p':'.':rest) -> rest ++ ".psx" -- anything -> anything ++ ".psx" Guess what: I did not work. dstfile was reversed (tmpfile ++ ".psx"). i guess this deals with lazy evalutation, but would be glad about some definit ideas. Matthias