[Haskell-cafe] Adding new entry to list

[Mrwibbly]

Hi all I'm having a problem trying to add a new record to a list. I need to
be able to add a new record to the database. My code is below, I also need
to work out the total sales for everything in the Sales list.

As you can see, I've tried to do it but I can't seem to work it out.

type Title = String
type Artist = String
type Sold = Int
--type Record = (Title, (Artist, Sold))
type Sales = [(Title, Artist, Sold)]

testDatabase :: Sales
testDatabase = [("Kids", "MGMT", 3), ("This Charming Man", "The Smiths", 5),
("Gimme Shelter", "The Rolling Stones", 7)]

totalSales :: Sales -> Title -> Artist -> Sold
totalSales [] title artist = 0
--totalSales ((t,a,n):testDatabase) title artist = title artist

--addSale :: Sales -> Sales
--addSale (Title, Artist, sold) = (title, artist, sold + 1)

--newRecord :: String -> String -> Sales -> Sales
--newRecord testDatabase title artist = (title, artist) ++ testDatabase

--newRecordAction :: Sales -> IO()
--newRecordAction testDatabase = do
	--putStrLn "Enter a new title: "
	--title <- getLine
	--putStrLn "Enter an artist: "
	--artist <- getLine
	--return $ newRecord title artist testDatabase

getTitle :: Sales -> Title
getTitle (title,_) = title
	
printNames :: Sales -> IO()
printNames testDatabase = mapM_ print testDatabase

mainLoop :: Sales -> IO()
mainLoop testDatabase = do
		putStrLn "1 - Show all tracks in database"
		putStrLn "2 - Exit"
		putStrLn ""
		putStrLn "Please select an option:"
		input <- getLine
		case read input of
			1 -> do
				putStrLn "------------------"
				putStrLn "Show All Tracks"
				putStrLn "------------------"
				printNames testDatabase
				putStrLn ""
				mainLoop testDatabase
			2 -> do
				return ()


main :: IO()
main = mainLoop testDatabase

Thank you,

Jack
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