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Within LTS Haskell 24.46 (ghc-9.10.3)

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1. filterMap :: (a -> Maybe b) -> Trie a -> Trie b

   bytestring-trie	Data.Trie

   Apply a function to all values, potentially removing them.

   Laws

   • Fission filterMap f ≡ fmap (fromJust . f) . filter (isJust . f)
   • Fusion fmap f . filter g ≡ filterMap (\v -> f v <$ guard (g v))
   • Conservation filterMap (Just . f) ≡ fmap f
   • Composition filterMap f . filterMap g ≡ filterMap (f <=< g)
   The fission/fusion laws are essentially the same, they differ only in which direction is more "natural" for use as a rewrite rule. The conservation law is just a special case of fusion, but it's a particularly helpful one to take note of.

2. submap :: ByteString -> Trie a -> Trie a

   bytestring-trie	Data.Trie

   Return the subtrie containing all keys beginning with a prefix.

3. contextualFilterMap :: (a -> Trie a -> Maybe b) -> Trie a -> Trie b

   bytestring-trie	Data.Trie.Internal

   Contextual variant of filterMap.

4. contextualMap :: (a -> Trie a -> b) -> Trie a -> Trie b

   bytestring-trie	Data.Trie.Internal

   A variant of fmap which provides access to the subtrie rooted at each value.

5. contextualMap' :: (a -> Trie a -> b) -> Trie a -> Trie b

   bytestring-trie	Data.Trie.Internal

   A variant of contextualMap which evaluates the function strictly.

6. contextualMapBy :: (ByteString -> a -> Trie a -> Maybe b) -> Trie a -> Trie b

   bytestring-trie	Data.Trie.Internal

   Contextual variant of mapBy, aka keyed variant of contextualFilterMap. Warning: This function suffers Bug #25.

7. filterMap :: (a -> Maybe b) -> Trie a -> Trie b

   bytestring-trie	Data.Trie.Internal

   Apply a function to all values, potentially removing them.

   Laws

   • Fission filterMap f ≡ fmap (fromJust . f) . filter (isJust . f)
   • Fusion fmap f . filter g ≡ filterMap (\v -> f v <$ guard (g v))
   • Conservation filterMap (Just . f) ≡ fmap f
   • Composition filterMap f . filterMap g ≡ filterMap (f <=< g)
   The fission/fusion laws are essentially the same, they differ only in which direction is more "natural" for use as a rewrite rule. The conservation law is just a special case of fusion, but it's a particularly helpful one to take note of.

8. submap :: ByteString -> Trie a -> Trie a

   bytestring-trie	Data.Trie.Internal

   Return the subtrie containing all keys beginning with a prefix.

9. buildDebVersionMap :: IO DebMap

   cabal-debian	Debian.Debianize

   Query versions of installed packages

10. dpkgFileMap :: IO (Map FilePath (Set BinPkgName))

    cabal-debian	Debian.Debianize

    Create a map from pathname to the names of the packages that contains that pathname using the contents of the debian package info directory varlibdpkginfo.

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