Add withRebuild.

src/Data/IxSet/Typed.hs

@@ -172,6 +172,7 @@ module Data.IxSet.Typed
      groupAscBy,
      groupDescBy,
      rebuild,
+     withRebuild,
 
      -- * Index creation helpers
      flatten,
@@ -563,6 +564,10 @@ insertList xs (IxSet a indexes) = IxSet (List.foldl' (\ b x -> Set.insert x b) a
         index' :: Map ix (Set a)
         index' = Ix.insertList dss index
 
+withRebuild :: IndexableWithIndex ixs ix a
+            => IxSet ixs a -> (IxSet ixs a -> IxSet '[ix] a) -> IxSet ixs a
+withRebuild ixset op = rebuild (op ixset)
+
 -- | Internal helper function that takes a partial index from one index
 -- set and rebuilds the rest of the structure of the index set.
 --

tests/Example.hs

@@ -39,7 +39,7 @@ t1 = UTCTime (fromGregorian 2014 03 06) 0
 t2 = UTCTime (fromGregorian 2012 12 12) 0
 t3 = UTCTime (fromGregorian 1909 09 09) 0
 
--- entries3 = rebuild (entries @= Author "john@doe.com") @< Updated t1
+entries3 = (entries `withRebuild` (@= Author "john@doe.com")) @< Updated t1
 
 newtype Word = Word String                            deriving (Show, Eq, Ord)
 newtype FirstAuthor = FirstAuthor Email               deriving (Show, Eq, Ord)