Changeset 14933 for src/Pugs/Prim/List.hs

Timestamp:

12/21/06 04:43:12 (2 years ago)

Author:

luqui

Message:

Implemented XX (but not the metaoperator).

Files:

• src/Pugs/Prim/List.hs (modified) (2 diffs)

src/Pugs/Prim/List.hs

@@ -2 +2 @@
 
 module Pugs.Prim.List (
-    op0Zip, op0Cat, op0Each, op0RoundRobin, op1Pick, op1Sum,
+    op0Zip, op0Cross, op0Cat, op0Each, op0RoundRobin, op1Pick, op1Sum,
     op1Min, op1Max, op1Uniq,
     op2Pick,
@@ -38 +38 @@
     zipRest  []     = []
     zipRest  (_:xs) = xs
+
+op0Cross :: [Val] -> Eval Val
+op0Cross = fmap (VList . fmap VList . op0Cross') . mapM fromVal
+
+op0Cross' :: [[Val]] -> [[Val]]
+op0Cross' [] = [[]]
+op0Cross' (xs:yss) = do
+    x <- xs
+    ys <- op0Cross' yss
+    return (x:ys)
 
 op1Pick :: Val -> Eval Val