Add a function deleteSubmap

src/Data/Trie/Text.hs

@@ -51,6 +51,9 @@ module Data.Trie.Text
 
     -- * Single-value modification
     , alterBy, insert, adjust, delete
+    , deleteSubmap
+    , deleteSubmap'
+    , deleteSubmap''
 
     -- * Combining tries
     , mergeBy, unionL, unionR
@@ -169,6 +172,12 @@ delete :: Text -> Trie a -> Trie a
 {-# INLINE delete #-}
 delete q = alterBy (\_ _ _ -> Nothing) q (impossible "delete")
 
+deleteSubmap'' key trie =
+    foldr
+        (\k t -> delete k t)
+        trie
+        (map L.toStrict . keys $ submap key trie)
+
 {---------------------------------------------------------------
 -- Trie-combining functions
 ---------------------------------------------------------------}

src/Data/Trie/Text/Internal.hs

@@ -56,6 +56,10 @@ module Data.Trie.Text.Internal
     , contextualFilterMap
     , contextualMapBy
 
+    -- * Something else
+    , deleteSubmap
+    , deleteSubmap'
+
     -- * Priority-queue functions
     , minAssoc, maxAssoc
     , updateMinViewBy, updateMaxViewBy
@@ -1012,6 +1016,34 @@ mergeMaybe _ mv0@(Just _) Nothing  = mv0
 mergeMaybe f (Just v0)   (Just v1) = f v0 v1
 
 
+-- | Delete the submap under the given key.
+deleteSubmap :: Text -> Trie a -> Trie a
+{-# INLINE deleteSubmap #-}
+deleteSubmap _ Empty            = Empty
+deleteSubmap q t@(Branch p m l r)
+    | nomatch qh p m  = t
+    | zero qh m       = branch p m (deleteSubmap q l) r
+    | otherwise       = branch p m l (deleteSubmap q r)
+    where
+    qh = errorLogHead "deleteSubmap" q
+deleteSubmap q (Arc k mv t) =
+    let (_,_,q') = breakMaximalPrefix k q in
+    case T.null q' of
+    True  -> -- Partially, or completely match the Prefix
+            Empty
+    False -> -- Have different Prefix yet, do nothing
+            arc k mv (deleteSubmap q' t)
+
+-- Inefficient implementation which is equivalent of `deleteSubmap`
+deleteSubmap' :: Text -> Trie a -> Trie a
+{-# INLINE deleteSubmap' #-}
+deleteSubmap' key trie =
+    foldr
+        (\k t -> alterBy (\_ _ _ -> Nothing) k (error "delete") t)
+        trie
+        (map L.toStrict . toListBy const $ submap key trie)
+
+
 {-----------------------------------------------------------
 -- Priority-queue functions
 -----------------------------------------------------------}

stack.yaml

@@ -1,6 +1,7 @@
 flags: {}
+resolver: lts-16.16
 packages:
 - .
 extra-deps:
-- bytestring-trie-0.2.5.0
-resolver: lts-13.15
+- bytestring-trie-0.2.5.0@sha256:9efa9c6f556314d28486be2470ff789419c5238ed2e354870623a3cbbd28fbe2,3349
+- microbench-0.1@sha256:f5c60aa2f40f9114aa0fb1fb2fe2f6cd8506d7ce3d1f0f46295d34651e523a2c,983

text-trie.cabal

@@ -73,9 +73,9 @@ Library
     -- The lower bounds are more restrictive than necessary.
     -- But then, we don't maintain any CI tests for older
     -- versions, so these are the lowest bounds we've verified.
-    Build-Depends: base       >= 4.5   && < 4.13
-                 , text       >= 1.2.3 && < 1.2.4
-                 , binary     >= 0.5.1 && < 0.8.7
+    Build-Depends: base       >= 4.5
+                 , text       >= 1.2.3
+                 , binary     >= 0.5.1
 
 ------------------------------------------------------------
 Test-Suite test-text-trie
@@ -90,16 +90,16 @@ Test-Suite test-text-trie
                   , FromListBench.Text.Encode
                   , TrieFile.Text
     build-depends: text-trie
-                 , base       >= 4.5   && < 4.13
-                 , bytestring >= 0.9.2 && < 0.11
-                 , text       >= 1.2.3 && < 1.2.4
-                 , binary     >= 0.5.1 && < 0.8.7
+                 , base       >= 4.5
+                 , bytestring >= 0.9.2
+                 , text       >= 1.2.3
+                 , binary     >= 0.5.1
                  , QuickCheck
                  , HUnit
                  , smallcheck
                  , microbench
-                 , bytestring-trie >= 0.2.5 && < 0.2.6
-                 , silently >= 1.2.5 && < 1.2.6
+                 , bytestring-trie >= 0.2.5
+                 , silently >= 1.2.5
 
 ------------------------------------------------------------
 ------------------------------------------------------- fin.