applebiz89 wrote:
becomeFan :: Title -> fanName -> [Film] -> [Film] becomeFan _ _ [] = [] becomeFan Title fanName ((Film Title Director Year fan):xs) | filmName == title = (Film Title Director Year fanName:fan) : xs | otherwise = (Film Title Director Year fan) : becomeFan Title fanName xs
In the type signature, you have to use types. In other words, use "Fan" instead of "fanName" in the first line. Variables have to begin with a lowercase letter. In other words, use "title", "director", "year" instead of "Title", "Director", "Year". Regarding the IO: I still propose to get your pure functions to work first, then worry about IO. You can test your code by loading it into ghci.
ghci nameofmyfile.hs
If everything works (i.e. no compile errors), you can call your functions at the prompt:
becomeFan "Casine Royale" "apple", testDatabase
Now ghci should answer with something like the following: [(Film "Casino Royale" "Martin Campbell" 2006 ["apple", "Garry", "Dave", "Zoe"])] This way, you can test your stuff while working on it. Tillmann