[Haskell-cafe] take the keywords from a string

Hi everybody, I have a function: takeKeyword :: String -> [String] This function will take the input as a string and return a list of keywords taken from the input string and they are elements of ListOfKeywords. The order of the result list is sequenced as: the last keyword found is set as the first element of the list, and so on. For example, ListOfKeywords = ["expand, "limit", "diff"] takeKeyword :: String -> [String] takeKeyword limit(x + expand((x+3)^2), x=3) = ["expand", "limit"] takeKeyword limit(x -7, x= 3) =["limit"] If you have any suggestions for that, please share with me. Thanks in advance. S.