99-haskell-problems/Problems 46-50/problem_48.hs

45 lines
853 B
Haskell

import Control.Monad (replicateM)
-- There isn't much point in implementing the basic predicates by hand
-- as it'd be equivalent to just writing their truth tables
and' :: Bool -> Bool -> Bool
and' = (&&)
infixl 4 `and'`
or' :: Bool -> Bool -> Bool
or' = (||)
infixl 3 `or'`
nand' :: Bool -> Bool -> Bool
nand' x y = not $ and' x y
infixl 9 `nand'`
nor' :: Bool -> Bool -> Bool
nor' x y = not $ or' x y
infixl 9 `nor'`
xor' :: Bool -> Bool -> Bool
xor' = (/=)
infixl 9 `xor'`
impl' :: Bool -> Bool -> Bool
impl' x = or' (not x)
infixl 3 `impl'`
equ' :: Bool -> Bool -> Bool
equ' = (==)
infixl 8 `equ'`
tablen :: Int -> ([Bool] -> Bool) -> IO ()
tablen n f = mapM_ putStrLn [toStr x ++ show (f x) | x <- replicateM n [True, False]]
where
toStr = unwords . map ((++) <$> show <*> space)
space True = " "
space False = " "