Add synonym for indexMaybe

haskell · Aug 21, 2020 · f2e918c · f2e918c
1 parent 32c6ed8
commit f2e918c
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diff --git a/Data/ByteString.hs b/Data/ByteString.hs
@@ -155,6 +155,7 @@ module Data.ByteString (
         -- * Indexing ByteStrings
         index,                  -- :: ByteString -> Int -> Word8
         indexMaybe,             -- :: ByteString -> Int -> Maybe Word8
+        (!?),                   -- :: ByteString -> Int -> Maybe Word8
         elemIndex,              -- :: Word8 -> ByteString -> Maybe Int
         elemIndices,            -- :: Word8 -> ByteString -> [Int]
         elemIndexEnd,           -- :: Word8 -> ByteString -> Maybe Int
@@ -1110,6 +1111,15 @@ indexMaybe ps n
     | otherwise      = Just $ ps `unsafeIndex` n
 {-# INLINE indexMaybe #-}
 
+-- | /O(1)/ 'ByteString' index, starting from 0, that returns 'Just' if:
+--
+-- > 0 <= n < length bs
+--
+-- @since 0.10.10.0
+(!?) :: ByteString -> Int -> Maybe Word8
+(!?) = indexMaybe
+{-# INLINE (!?) #-}
+
 -- | /O(n)/ The 'elemIndex' function returns the index of the first
 -- element in the given 'ByteString' which is equal to the query
 -- element, or 'Nothing' if there is no such element.

diff --git a/Data/ByteString/Char8.hs b/Data/ByteString/Char8.hs
@@ -165,6 +165,7 @@ module Data.ByteString.Char8 (
         -- * Indexing ByteStrings
         index,                  -- :: ByteString -> Int -> Char
         indexMaybe,             -- :: ByteString -> Int -> Maybe Char
+        (!?),                   -- :: ByteString -> Int -> Maybe Char
         elemIndex,              -- :: Char -> ByteString -> Maybe Int
         elemIndices,            -- :: Char -> ByteString -> [Int]
         elemIndexEnd,           -- :: Char -> ByteString -> Maybe Int
@@ -654,6 +655,15 @@ indexMaybe :: ByteString -> Int -> Maybe Char
 indexMaybe = ((fmap w2c) .) . B.indexMaybe
 {-# INLINE indexMaybe #-}
 
+-- | /O(1)/ 'ByteString' index, starting from 0, that returns 'Just' if:
+--
+-- > 0 <= n < length bs
+--
+-- @since 0.10.10.0
+(!?) :: ByteString -> Int -> Maybe Char
+(!?) = indexMaybe
+{-# INLINE (!?) #-}
+
 -- | /O(n)/ The 'elemIndex' function returns the index of the first
 -- element in the given 'ByteString' which is equal (by memchr) to the
 -- query element, or 'Nothing' if there is no such element.

diff --git a/Data/ByteString/Lazy.hs b/Data/ByteString/Lazy.hs
@@ -168,6 +168,7 @@ module Data.ByteString.Lazy (
         -- * Indexing ByteStrings
         index,                  -- :: ByteString -> Int64 -> Word8
         indexMaybe,             -- :: ByteString -> Int64 -> Maybe Word8
+        (!?),                   -- :: ByteString -> Int64 -> Maybe Word8
         elemIndex,              -- :: Word8 -> ByteString -> Maybe Int64
         elemIndexEnd,           -- :: Word8 -> ByteString -> Maybe Int64
         elemIndices,            -- :: Word8 -> ByteString -> [Int64]
@@ -910,6 +911,15 @@ indexMaybe cs0 i       = index' cs0 i
               index' cs (n - fromIntegral (S.length c))
           | otherwise       = Just $ S.unsafeIndex c (fromIntegral n)
 
+-- | /O(1)/ 'ByteString' index, starting from 0, that returns 'Just' if:
+--
+-- > 0 <= n < length bs
+--
+-- @since 0.10.10.0
+(!?) :: ByteString -> Int64 -> Maybe Word8
+(!?) = indexMaybe
+{-# INLINE (!?) #-}
+
 -- | /O(n)/ The 'elemIndex' function returns the index of the first
 -- element in the given 'ByteString' which is equal to the query
 -- element, or 'Nothing' if there is no such element.

diff --git a/Data/ByteString/Lazy/Char8.hs b/Data/ByteString/Lazy/Char8.hs
@@ -147,6 +147,7 @@ module Data.ByteString.Lazy.Char8 (
         -- * Indexing ByteStrings
         index,                  -- :: ByteString -> Int64 -> Char
         indexMaybe,             -- :: ByteString -> Int64 -> Maybe Char
+        (!?),                   -- :: ByteString -> Int64 -> Maybe Char
         elemIndex,              -- :: Char -> ByteString -> Maybe Int64
         elemIndices,            -- :: Char -> ByteString -> [Int64]
         findIndex,              -- :: (Char -> Bool) -> ByteString -> Maybe Int64
@@ -537,6 +538,15 @@ indexMaybe :: ByteString -> Int64 -> Maybe Char
 indexMaybe = ((fmap w2c) .) . L.indexMaybe
 {-# INLINE indexMaybe #-}
 
+-- | /O(1)/ 'ByteString' index, starting from 0, that returns 'Just' if:
+--
+-- > 0 <= n < length bs
+--
+-- @since 0.10.10.0
+(!?) :: ByteString -> Int64 -> Maybe Char
+(!?) = indexMaybe
+{-# INLINE (!?) #-}
+
 -- | /O(n)/ The 'elemIndex' function returns the index of the first
 -- element in the given 'ByteString' which is equal (by memchr) to the
 -- query element, or 'Nothing' if there is no such element.