Merge pull request #29 from phadej/unzip

Add unzip example

Author: edsko

examples/unzip.hs

@@ -0,0 +1,17 @@
+-- example that unzip does some work before returning the result pair
+
+-- some generator which does some work before producing the elements of a list
+generate = (\x -> \y ->
+  if le y 0 then Nil else
+  if le x 0 then Nil else
+  Cons (Pair x y) (@generate (sub x 1) (sub y 1))
+  )
+
+unzip = (\xs -> case xs of {
+  Nil -> Pair Nil Nil;
+  Cons xy xys -> case xy of {
+    Pair x y -> let r = @unzip xys in Pair (Cons x (fst r)) (Cons y (snd r))
+  }
+  })
+
+main = @unzip (@generate 1 2)