FoldDir.hs wip

tianyicui · Nov 28, 2010 · ab2105a · ab2105a
1 parent 19bf85b
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diff --git a/ch09/ControlledVisit.hs b/ch09/ControlledVisit.hs
@@ -1,5 +1,7 @@
 {-# LANGUAGE ScopedTypeVariables, NoMonomorphismRestriction #-}
 
+module ControlledVisit where
+
 import Data.List(sortBy)
 import Data.Ord(comparing)
 import Control.Monad (forM, liftM)

diff --git a/ch09/FoldDir.hs b/ch09/FoldDir.hs
@@ -0,0 +1,10 @@
+module FoldDir where
+
+import ControlledVisit
+
+data Iterate seed = Done     { unwrap :: seed }
+                  | Skip     { unwrap :: seed }
+                  | Continue { unwrap :: seed }
+                    deriving (Show)
+
+type Iterator seed = seed -> Info -> Iterate seed