Data commit

Task/Stack/Haskell/stack-1.hs

@@ -0,0 +1,18 @@
+type Stack a = [a]
+
+create :: Stack a
+create = []
+
+push :: a -> Stack a -> Stack a
+push = (:)
+
+pop :: Stack a -> (a, Stack a)
+pop []     = error "Stack empty"
+pop (x:xs) = (x,xs)
+
+empty :: Stack a -> Bool
+empty = null
+
+peek :: Stack a -> a
+peek []    = error "Stack empty"
+peek (x:_) = x