phiroc@free.fr wrote:
Ketil,
thanks for you help.
Here's the code:
and2 :: Bool -> Bool -> Bool and2 a b = a && b
loop = [ and2 x y | x <- [True,False], y <- [True,False] ]
Now, how do I have Haskell print
printStrLn("True and True = ") + <result of calling and2 True True> printStrLn("True and False = ") + <result of calling and2 True False>
Well, if you keep x and y in the table as well, either as a triple (x, y, and2 x y) or a nested tuple ((x,y), and2 x y) (which would let you use the lookup function), you can define a function that converts such a tuple to the approprate string. Keep in mind that Bool has a Show instance, so that e.g. show True => "True", and use ++ to join two strings. Then, you can 'map' this function on the table to get a list of strings corresponding to table rows, and use 'concat' or 'unlines'. When you have a result you're happy with, you feed it to putStrLn. -k