Safe Haskell	None
Language	Haskell2010

FastString

Contents

ByteString
FastZString
FastStrings
PtrStrings

Description

There are two principal string types used internally by GHC:

FastString

A compact, hash-consed, representation of character strings.
Comparison is O(1), and you can get a Unique from them.
Generated by fsLit.
Turn into SDoc with ftext.

PtrString

Pointer and size of a Latin-1 encoded string.
Practically no operations.
Outputing them is fast.
Generated by sLit.
Turn into SDoc with ptext
Requires manual memory management. Improper use may lead to memory leaks or dangling pointers.
It assumes Latin-1 as the encoding, therefore it cannot represent arbitrary Unicode strings.

Use PtrString unless you want the facilities of FastString.

Synopsis

bytesFS :: FastString -> ByteString
fastStringToByteString :: FastString -> ByteString
mkFastStringByteString :: ByteString -> FastString
fastZStringToByteString :: FastZString -> ByteString
unsafeMkByteString :: String -> ByteString
data FastZString
hPutFZS :: Handle -> FastZString -> IO ()
zString :: FastZString -> String
lengthFZS :: FastZString -> Int
data FastString = FastString {
- uniq :: !Int
- n_chars :: !Int
- fs_bs :: !ByteString
- fs_zenc :: FastZString
}
fsLit :: String -> FastString
mkFastString :: String -> FastString
mkFastStringBytes :: Ptr Word8 -> Int -> FastString
mkFastStringByteList :: [Word8] -> FastString
mkFastStringForeignPtr :: Ptr Word8 -> ForeignPtr Word8 -> Int -> IO FastString
mkFastString# :: Addr# -> FastString
unpackFS :: FastString -> String
zEncodeFS :: FastString -> FastZString
uniqueOfFS :: FastString -> Int
lengthFS :: FastString -> Int
nullFS :: FastString -> Bool
appendFS :: FastString -> FastString -> FastString
headFS :: FastString -> Char
tailFS :: FastString -> FastString
concatFS :: [FastString] -> FastString
consFS :: Char -> FastString -> FastString
nilFS :: FastString
isUnderscoreFS :: FastString -> Bool
hPutFS :: Handle -> FastString -> IO ()
getFastStringTable :: IO [[[FastString]]]
getFastStringZEncCounter :: IO Int
data PtrString = PtrString !(Ptr Word8) !Int
sLit :: String -> PtrString
mkPtrString# :: Addr# -> PtrString
mkPtrString :: String -> PtrString
unpackPtrString :: PtrString -> String
lengthPS :: PtrString -> Int

ByteString

bytesFS :: FastString -> ByteString Source #

Gives the UTF-8 encoded bytes corresponding to a FastString

fastStringToByteString :: FastString -> ByteString Source #

Deprecated: Use bytesFS instead

mkFastStringByteString :: ByteString -> FastString Source #

Create a FastString from an existing ForeignPtr; the difference between this and mkFastStringBytes is that we don't have to copy the bytes if the string is new to the table.

fastZStringToByteString :: FastZString -> ByteString Source #

unsafeMkByteString :: String -> ByteString Source #

FastZString

data FastZString Source #

Instances

NFData FastZString Source #
Instance details Defined in FastString Methods rnf :: FastZString -> () #

hPutFZS :: Handle -> FastZString -> IO () Source #

zString :: FastZString -> String Source #

lengthFZS :: FastZString -> Int Source #

FastStrings

data FastString Source #

A FastString is a UTF-8 encoded string together with a unique ID. All FastStrings are stored in a global hashtable to support fast O(1) comparison.

It is also associated with a lazy reference to the Z-encoding of this string which is used by the compiler internally.

Constructors

FastString
Fields uniq :: !Int n_chars :: !Int fs_bs :: !ByteString fs_zenc :: FastZString Lazily computed z-encoding of this string. Since `FastString`s are globally memoized this is computed at most once for any given string.

Instances

Eq FastString Source #
Instance details Defined in FastString Methods (==) :: FastString -> FastString -> Bool # (/=) :: FastString -> FastString -> Bool #
Data FastString Source #
Instance details Defined in FastString Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> FastString -> c FastString # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c FastString # toConstr :: FastString -> Constr # dataTypeOf :: FastString -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c FastString) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FastString) # gmapT :: (forall b. Data b => b -> b) -> FastString -> FastString # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> FastString -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> FastString -> r # gmapQ :: (forall d. Data d => d -> u) -> FastString -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> FastString -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> FastString -> m FastString # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> FastString -> m FastString # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> FastString -> m FastString #
Ord FastString Source #
Instance details Defined in FastString Methods compare :: FastString -> FastString -> Ordering # (<) :: FastString -> FastString -> Bool # (<=) :: FastString -> FastString -> Bool # (>) :: FastString -> FastString -> Bool # (>=) :: FastString -> FastString -> Bool # max :: FastString -> FastString -> FastString # min :: FastString -> FastString -> FastString #
Show FastString Source #
Instance details Defined in FastString Methods showsPrec :: Int -> FastString -> ShowS # show :: FastString -> String # showList :: [FastString] -> ShowS #
IsString FastString Source #
Instance details Defined in FastString Methods fromString :: String -> FastString #
Semigroup FastString Source #
Instance details Defined in FastString Methods (<>) :: FastString -> FastString -> FastString # sconcat :: NonEmpty FastString -> FastString # stimes :: Integral b => b -> FastString -> FastString #
Monoid FastString Source #
Instance details Defined in FastString Methods mempty :: FastString # mappend :: FastString -> FastString -> FastString # mconcat :: [FastString] -> FastString #
NFData FastString Source #
Instance details Defined in FastString Methods rnf :: FastString -> () #
Outputable FastString Source #
Instance details Defined in Outputable Methods ppr :: FastString -> SDoc Source # pprPrec :: Rational -> FastString -> SDoc Source #
Uniquable FastString Source #
Instance details Defined in Unique Methods getUnique :: FastString -> Unique Source #
Binary FastString Source #
Instance details Defined in Binary Methods put_ :: BinHandle -> FastString -> IO () Source # put :: BinHandle -> FastString -> IO (Bin FastString) Source # get :: BinHandle -> IO FastString Source #

Construction

fsLit :: String -> FastString Source #

mkFastString :: String -> FastString Source #

Creates a UTF-8 encoded FastString from a String

mkFastStringBytes :: Ptr Word8 -> Int -> FastString Source #

mkFastStringByteList :: [Word8] -> FastString Source #

Creates a FastString from a UTF-8 encoded [Word8]

mkFastStringForeignPtr :: Ptr Word8 -> ForeignPtr Word8 -> Int -> IO FastString Source #

Create a FastString from an existing ForeignPtr; the difference between this and mkFastStringBytes is that we don't have to copy the bytes if the string is new to the table.

mkFastString# :: Addr# -> FastString Source #

Deconstruction

unpackFS :: FastString -> String Source #

Unpacks and decodes the FastString

Encoding

zEncodeFS :: FastString -> FastZString Source #

Returns a Z-encoded version of a FastString. This might be the original, if it was already Z-encoded. The first time this function is applied to a particular FastString, the results are memoized.

Operations

uniqueOfFS :: FastString -> Int Source #

lengthFS :: FastString -> Int Source #

Returns the length of the FastString in characters

nullFS :: FastString -> Bool Source #

Returns True if the FastString is empty

appendFS :: FastString -> FastString -> FastString Source #

headFS :: FastString -> Char Source #

tailFS :: FastString -> FastString Source #

concatFS :: [FastString] -> FastString Source #

consFS :: Char -> FastString -> FastString Source #

nilFS :: FastString Source #

isUnderscoreFS :: FastString -> Bool Source #

Outputing

hPutFS :: Handle -> FastString -> IO () Source #

Outputs a FastString with no decoding at all, that is, you get the actual bytes in the FastString written to the Handle.

Internal

getFastStringTable :: IO [[[FastString]]] Source #

getFastStringZEncCounter :: IO Int Source #

PtrStrings

data PtrString Source #

A PtrString is a pointer to some array of Latin-1 encoded chars.

Constructors

PtrString !(Ptr Word8) !Int

Construction

sLit :: String -> PtrString Source #

mkPtrString# :: Addr# -> PtrString Source #

Wrap an unboxed address into a PtrString.

mkPtrString :: String -> PtrString Source #

Encode a String into a newly allocated PtrString using Latin-1 encoding. The original string must not contain non-Latin-1 characters (above codepoint 0xff).

Deconstruction

unpackPtrString :: PtrString -> String Source #

Decode a PtrString back into a String using Latin-1 encoding. This does not free the memory associated with PtrString.

Operations

lengthPS :: PtrString -> Int Source #

Return the length of a PtrString