GHC.Read

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GHC.Read |
Portability | non-portable (GHC Extensions)
Stability | internal
Maintainer | cvs-ghc@haskell.org
Description
The `Read` class and instances for basic data types.
Synopsis
class Read a where
readListPrec :: ReadPrec [a]
readPrec :: ReadPrec a
readList :: ReadS [a]
readsPrec :: Int -> ReadS a
type ReadS a = String -> [(a, String)]
reads :: (Read a) => ReadS a
readp :: (Read a) => ReadP a
readEither :: (Read a) => String -> Either String a
read :: (Read a) => String -> a
lex :: ReadS String
lexLitChar :: ReadS String
readLitChar :: ReadS Char
lexDigits :: ReadS String
lexP :: ReadPrec Lexeme
paren :: ReadPrec a -> ReadPrec a
parens :: ReadPrec a -> ReadPrec a
list :: ReadPrec a -> ReadPrec [a]
choose :: [(String, ReadPrec a)] -> ReadPrec a
readListDefault :: (Read a) => ReadS [a]
readListPrecDefault :: (Read a) => ReadPrec [a]
readList__ :: ReadS a -> ReadS [a]
readParen :: Bool -> ReadS a -> ReadS a
Documentation
class Read a where
Methods
readListPrec :: ReadPrec [a]
readPrec :: ReadPrec a
readList :: ReadS [a]
readsPrec :: Int -> ReadS a
Instances
Read CChar
Read CSChar
Read CUChar
Read CShort
Read CUShort
Read CInt
Read CUInt
Read CLong
Read CULong
Read CLLong
Read CULLong
Read CFloat
Read CDouble
Read CLDouble
Read CPtrdiff
Read CSize
Read CWchar
Read CSigAtomic
Read CClock
Read CTime
Read Int8
Read Int16
Read Int32
Read Int64
Read Char
Read Bool
Read Ordering
(Read a) => Read (Maybe a)
(Read a, Read b) => Read (Either a b)
(Read a) => Read [a]
(Ix a, Read a, Read b) => Read (Array a b)
Read Lexeme
Read Int
Read Integer
Read Float
Read Double
(Integral a, Read a) => Read (Ratio a)
Read ()
(Read a, Read b) => Read (a, b)
(Read a, Read b, Read c) => Read (a, b, c)
(Read a, Read b, Read c, Read d) => Read (a, b, c, d)
(Read a, Read b, Read c, Read d, Read e) => Read (a, b, c, d, e)
Read Word
Read Word8
Read Word16
Read Word32
Read Word64
Read StdGen
type ReadS a = String -> [(a, String)]
A parser for a type `a`, represented as a function that takes a `String` and returns a list of possible parses `(a,`String`)` pairs.
reads :: (Read a) => ReadS a
readp :: (Read a) => ReadP a
readEither :: (Read a) => String -> Either String a
read :: (Read a) => String -> a
lex :: ReadS String
lexLitChar :: ReadS String
readLitChar :: ReadS Char
lexDigits :: ReadS String
lexP :: ReadPrec Lexeme
Parse a single lexeme
paren :: ReadPrec a -> ReadPrec a
`(paren p)` parses (P0) where `p` parses P0 in precedence context zero
parens :: ReadPrec a -> ReadPrec a
`(parens p)` parses P, (P0), ((P0)), etc, where `p` parses P in the current precedence context parses P0 in precedence context zero
list :: ReadPrec a -> ReadPrec [a]
`(list p)` parses a list of things parsed by `p`, using the usual square-bracket syntax.
choose :: [(String, ReadPrec a)] -> ReadPrec a
Parse the specified lexeme and continue as specified. Esp useful for nullary constructors; e.g. `choose [(A, return A), (B, return B)]`
readListDefault :: (Read a) => ReadS [a]
Use this to define the `readList` method, if you don't want a special case
readListPrecDefault :: (Read a) => ReadPrec [a]
Use this to define the `readListPrec` method, if you don't want a special case
readList__ :: ReadS a -> ReadS [a]
readParen :: Bool -> ReadS a -> ReadS a
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