Quoth phiroc@free.fr, nevermore,
loop = do and True True and True False and False True and False False
For this construct to work you'd have to have 'and' as a monadic function - let's say, for argument's sake, in IO. And because there are no results being carried around we can surmise that the type signature is:
and :: Bool -> Bool -> IO ()
This will help you do the putStr statements too, although I think it can be done better. For example, you want to create a truth table, and you want to print the values of this table. These should really be done separately, so you don't mix IO with pure computation. You might want to write a function of the type:
and :: Bool -> Bool -> (Bool, Bool, Bool)
instead, where the two arguments passed in are stored alongside the result.
Is there a better way to repeatedly call "and"?
Furthermore, is there a way in Haskell to loop through the Boolean values (True and False) and call "and" each time?
These can be answered in one sweep with list comprehensions. An expression of the form [ f x y | x <- xs, y <- ys ] will form a list where every value is 'f x y' for all values of x and y in the two source lists xs and ys. I hope this is of some help. I've been purposefully vague in case this is a homework question. If not, let us know and I'm sure people will be more than happy to provide fuller answers. Cheers, D.