Dear Haskell-Cafe, Every now and then I get error messages when compiling Haskell code :). Sometimes of the sort: test.hs:10:15: Couldn't match type `[[a2]]' with `Int' Expected type: Int -> Int Actual type: [[a2]] -> Int The function `length . head' is applied to one argument, but its type `[[a2]] -> Int' has only one In the first argument of `(==)', namely `(length . head) r' In the expression: (length . head) r == 0 Is the middle part of the error message (The function `length . head' is applied to one argument, but its type `[[a2]] -> Int' has only one) expected to be confusing like that sometimes? The line in question, FWIW, is Right r -> if (length . head) r == 0 It appears as one of the two entries in a case statement, pattern matching on Right constructor. Many thanks, S. -- Семен Тригубенко http://trygub.com