Add documentation for filter function with custom scoring function

Replace all functions using previous filter without custom scoring
with a call to the new filter function where the scoring function is the basic match function.

ghcide/src/Development/IDE/Plugin/Completions/Logic.hs

@@ -585,7 +585,7 @@ getCompletions plugins ideOpts CC {allModNamesAsNS, anyQualCompls, unqualCompls,
           $ (if T.null enteredQual then id else mapMaybe (T.stripPrefix enteredQual))
             allModNamesAsNS
 
-      filtCompls = Fuzzy.filter chunkSize maxC prefixText ctxCompls (label . snd)
+      filtCompls = Fuzzy.filter chunkSize maxC prefixText ctxCompls (label . snd) Fuzzy.match
         where
 
           mcc = case maybe_parsed of

ghcide/src/Text/Fuzzy/Parallel.hs

@@ -1,7 +1,7 @@
 -- | Parallel versions of 'filter' and 'simpleFilter'
 
 module Text.Fuzzy.Parallel
-(   filter, filter',
+(   filter,
     simpleFilter, simpleFilter',
     match, defChunkSize, defMaxResults,
     Scored(..)
@@ -29,7 +29,6 @@ data Scored a = Scored {score :: !Int, original:: !a}
 -- Just 5
 --
 {-# INLINABLE match #-}
-
 match :: T.Text    -- ^ Pattern in lowercase except for first character
       -> T.Text    -- ^ The text to search in.
       -> Maybe Int -- ^ The score
@@ -70,23 +69,6 @@ match (T.Text pArr pOff pLen) (T.Text sArr sOff sLen) = go 0 1 pOff sOff
 
     toLowerAscii w = if (w - 65) < 26 then w .|. 0x20 else w
 
--- | The function to filter a list of values by fuzzy search on the text extracted from them.
-filter :: Int           -- ^ Chunk size. 1000 works well.
-       -> Int           -- ^ Max. number of results wanted
-       -> T.Text        -- ^ Pattern.
-       -> [t]           -- ^ The list of values containing the text to search in.
-       -> (t -> T.Text) -- ^ The function to extract the text from the container.
-       -> [Scored t]    -- ^ The list of results, sorted, highest score first.
-filter chunkSize maxRes pattern ts extract = partialSortByAscScore maxRes perfectScore (concat vss)
-  where
-      -- Preserve case for the first character, make all others lowercase
-      pattern' = case T.uncons pattern of
-        Just (c, rest) -> T.cons c (T.toLower rest)
-        _              -> pattern
-      vss = map (mapMaybe (\t -> flip Scored t <$> match pattern' (extract t))) (chunkList chunkSize ts)
-        `using` parList (evalList rseq)
-      perfectScore = fromMaybe (error $ T.unpack pattern) $ match pattern' pattern'
-
 -- | Sensible default value for chunk size to use when calling simple filter.
 defChunkSize :: Int
 defChunkSize = 1000
@@ -108,18 +90,21 @@ simpleFilter :: Int      -- ^ Chunk size. 1000 works well.
              -> [T.Text] -- ^ List of texts to check.
              -> [Scored T.Text] -- ^ The ones that match.
 simpleFilter chunk maxRes pattern xs =
-  filter chunk maxRes pattern xs id
+  filter chunk maxRes pattern xs id match
 
 
--- | The function to filter a list of values by fuzzy search on the text extracted from them.
-filter' :: Int           -- ^ Chunk size. 1000 works well.
+-- | The function to filter a list of values by fuzzy search on the text extracted from them,
+-- using a custom matching function which determines how close words are.
+filter :: Int           -- ^ Chunk size. 1000 works well.
        -> Int           -- ^ Max. number of results wanted
        -> T.Text        -- ^ Pattern.
        -> [t]           -- ^ The list of values containing the text to search in.
        -> (t -> T.Text) -- ^ The function to extract the text from the container.
-       -> (T.Text -> T.Text -> Maybe Int) -- ^ Function to use for matching
+       -> (T.Text -> T.Text -> Maybe Int)
+       -- ^ Custom scoring function to use for calculating how close words are
+       -- When the function returns Nothing, this means the values are incomparable.
        -> [Scored t]    -- ^ The list of results, sorted, highest score first.
-filter' chunkSize maxRes pattern ts extract match' = partialSortByAscScore maxRes perfectScore (concat vss)
+filter chunkSize maxRes pattern ts extract match' = partialSortByAscScore maxRes perfectScore (concat vss)
   where
       -- Preserve case for the first character, make all others lowercase
       pattern' = case T.uncons pattern of
@@ -129,21 +114,19 @@ filter' chunkSize maxRes pattern ts extract match' = partialSortByAscScore maxRe
         `using` parList (evalList rseq)
       perfectScore = fromMaybe (error $ T.unpack pattern) $ match' pattern' pattern'
 
--- | Return all elements of the list that have a fuzzy
--- match against the pattern, using a custom match function. Runs with default settings where
--- nothing is added around the matches, as case insensitive.
---
--- >>> simpleFilter 1000 10 "vm" ["vim", "emacs", "virtual machine"]
--- [Scored {score = 4, original = "vim"},Scored {score = 4, original = "virtual machine"}]
+-- | Return all elements of the list that have a fuzzy match against the pattern,
+-- the closeness of the match is determined using the custom scoring match function that is passed.
+-- Runs with default settings where nothing is added around the matches, as case insensitive.
 {-# INLINABLE simpleFilter' #-}
 simpleFilter' :: Int      -- ^ Chunk size. 1000 works well.
              -> Int      -- ^ Max. number of results wanted
              -> T.Text   -- ^ Pattern to look for.
              -> [T.Text] -- ^ List of texts to check.
-             -> (T.Text -> T.Text -> Maybe Int) -- ^ Function to use for matching
+             -> (T.Text -> T.Text -> Maybe Int)
+             -- ^ Custom scoring function to use for calculating how close words are
              -> [Scored T.Text] -- ^ The ones that match.
 simpleFilter' chunk maxRes pattern xs match' =
-  filter' chunk maxRes pattern xs id match'
+  filter chunk maxRes pattern xs id match'
 --------------------------------------------------------------------------------
 
 chunkList :: Int -> [a] -> [[a]]