Hi TP,
What is the reason for this message?
'f' and 'g' in the 'case' expression are local names/bindings and have nothing in common with the 'f' and 'g' functions. It's the same like introducing names/bindings with the 'let' expression: let f = ... g = ... in ... The bindings are overlapping, because both match all the time and GHC will always use the first one.
Why does it not work? If Mult and Plus are functions, then I should not need to put their arguments in pattern matching.
'Mult' and 'Plus' are data constructors which both expect one argument: a 'Float'. You also can't match the data constructors against a function, but only against a value of its type. pat :: Foobar -> Bool pat t = case t of Mult f -> True Plus f -> False Greetings, Daniel