isTypeId, isValueId

People, I need to implement the functions isTypeId, isValueId :: String -> Bool which check whether the argument fits respectively the syntax of a type identifier and of a value identifier -- in the Haskell-98 syntax for a program. The argument is produced by lexLots. For example, my program applies lexLots "ab-(f_21 -- I expect: ["ab", "-", "(", "f_21", "<", "Ab", ":", "c"] -- 1 2 3 4 Then, I think, only (1), (2), (3) and (4) are type or value identifiers ... What is the most regular expression for isTypeId, isValueId ? I presume to consider first the Standard library, and if fail, then the GHC library. Thank you in advance for your advice. Regards, ----------------- Serge Mechveliani mechvel@botik.ru