Haskell Hierarchical Libraries (base package)ContentsIndex
GHC.Exts
Portability non-portable (GHC Extensions)
Stability internal
Maintainer cvs-ghc@haskell.org
Contents
Representations of some basic types
Primitive operations
Fusion
Linear implicit parameter support
Description
GHC Extensions: this is the Approved Way to get at GHC-specific extensions.
Synopsis
data Int = I# Int#
data Word = W# Word#
data Float = F# Float#
data Double = D# Double#
data Integer
= S# Int#
| J# Int# ByteArray#
data Char = C# Char#
data Ptr a = Ptr Addr#
data FunPtr a = FunPtr Addr#
shiftL# :: Word# -> Int# -> Word#
shiftRL# :: Word# -> Int# -> Word#
iShiftL# :: Int# -> Int# -> Int#
iShiftRA# :: Int# -> Int# -> Int#
iShiftRL# :: Int# -> Int# -> Int#
build :: forall a . (forall b . (a -> b -> b) -> b -> b) -> [a]
augment :: forall a . (forall b . (a -> b -> b) -> b -> b) -> [a] -> [a]
class Splittable t where
split :: t -> (t, t)
Representations of some basic types
data Int
A fixed-precision integer type with at least the range [-2^29 .. 2^29-1]. The exact range for a given implementation can be determined by using minBound and maxBound from the Bounded class.
Constructors
I# Int#
Instances
IArray UArray Int
Ix ix => Eq (UArray ix Int)
Ix ix => Ord (UArray ix Int)
(Ix ix, Show ix) => Show (UArray ix Int)
MArray (STUArray s) Int (ST s)
(Ix ix, Show ix) => Show (DiffUArray ix Int)
IArray (IOToDiffArray IOUArray) Int
MArray IOUArray Int IO
Bits Int
Data Int
Typeable Int
Storable Int
Ix Int
Eq Int
Ord Int
Bounded Int
Enum Int
Num Int
Read Int
Real Int
Integral Int
Show Int
Random Int
data Word
A Word is an unsigned integral type, with the same size as Int.
Constructors
W# Word#
Instances
IArray UArray Word
Ix ix => Eq (UArray ix Word)
Ix ix => Ord (UArray ix Word)
(Ix ix, Show ix) => Show (UArray ix Word)
MArray (STUArray s) Word (ST s)
(Ix ix, Show ix) => Show (DiffUArray ix Word)
IArray (IOToDiffArray IOUArray) Word
MArray IOUArray Word IO
Storable Word
Show Word
Num Word
Real Word
Enum Word
Integral Word
Bounded Word
Ix Word
Read Word
Bits Word
Eq Word
Ord Word
data Float
Single-precision floating point numbers.
Constructors
F# Float#
Instances
IArray UArray Float
Ix ix => Eq (UArray ix Float)
Ix ix => Ord (UArray ix Float)
(Ix ix, Show ix) => Show (UArray ix Float)
MArray (STUArray s) Float (ST s)
(Ix ix, Show ix) => Show (DiffUArray ix Float)
IArray (IOToDiffArray IOUArray) Float
MArray IOUArray Float IO
Data Float
Typeable Float
Storable Float
Eq Float
Ord Float
Num Float
Real Float
Fractional Float
RealFrac Float
Floating Float
RealFloat Float
Show Float
Enum Float
Read Float
Random Float
data Double
Double-precision floating point numbers.
Constructors
D# Double#
Instances
IArray UArray Double
Ix ix => Eq (UArray ix Double)
Ix ix => Ord (UArray ix Double)
(Ix ix, Show ix) => Show (UArray ix Double)
MArray (STUArray s) Double (ST s)
(Ix ix, Show ix) => Show (DiffUArray ix Double)
IArray (IOToDiffArray IOUArray) Double
MArray IOUArray Double IO
Typeable Double
Storable Double
Eq Double
Ord Double
Num Double
Real Double
Fractional Double
Floating Double
RealFrac Double
RealFloat Double
Show Double
Enum Double
Read Double
Random Double
data Integer
Arbitrary-precision integers.
Constructors
S# Int#
J# Int# ByteArray#
Instances
Bits Integer
Data Integer
Typeable Integer
Ix Integer
Eq Integer
Ord Integer
Num Integer
Enum Integer
Show Integer
Read Integer
Real Integer
Integral Integer
Random Integer
data Char

The character type Char is an enumeration whose values represent Unicode (or equivalently ISO 10646) characters. This set extends the ISO 8859-1 (Latin-1) character set (the first 256 charachers), which is itself an extension of the ASCII character set (the first 128 characters). A character literal in Haskell has type Char.

To convert a Char to or from the corresponding Int value defined by Unicode, use toEnum and fromEnum from the Enum class respectively (or equivalently ord and chr).

Constructors
C# Char#
Instances
Error [Char]
IArray UArray Char
Ix ix => Eq (UArray ix Char)
Ix ix => Ord (UArray ix Char)
(Ix ix, Show ix) => Show (UArray ix Char)
MArray (STUArray s) Char (ST s)
(Ix ix, Show ix) => Show (DiffUArray ix Char)
IArray (IOToDiffArray IOUArray) Char
MArray IOUArray Char IO
Data Char
Typeable Char
Storable Char
Ix Char
Eq Char
Ord Char
Bounded Char
Enum Char
Read Char
Show Char
Random Char
HTML Char
data Ptr a

A value of type Ptr a represents a pointer to an object, or an array of objects, which may be marshalled to or from Haskell values of type a.

The type a will often be an instance of class Storable which provides the marshalling operations. However this is not essential, and you can provide your own operations to access the pointer. For example you might write small foreign functions to get or set the fields of a C struct.

Constructors
Ptr Addr#
Instances
IArray UArray (Ptr a)
Ix ix => Eq (UArray ix (Ptr a))
Ix ix => Ord (UArray ix (Ptr a))
MArray (STUArray s) (Ptr a) (ST s)
IArray (IOToDiffArray IOUArray) (Ptr a)
MArray IOUArray (Ptr a) IO
Typeable a => Typeable (Ptr a)
Show (Ptr a)
Storable (Ptr a)
Eq (Ptr a)
Ord (Ptr a)
data FunPtr a

A value of type FunPtr a is a pointer to a function callable from foreign code. The type a will normally be a foreign type, a function type with zero or more arguments where

A value of type FunPtr a may be a pointer to a foreign function, either returned by another foreign function or imported with a a static address import like

 foreign import ccall "stdlib.h &free"
   p_free :: FunPtr (Ptr a -> IO ())

or a pointer to a Haskell function created using a wrapper stub declared to produce a FunPtr of the correct type. For example:

 type Compare = Int -> Int -> Bool
 foreign import ccall "wrapper"
   mkCompare :: Compare -> IO (FunPtr Compare)

Calls to wrapper stubs like mkCompare allocate storage, which should be released with freeHaskellFunPtr when no longer required.

To convert FunPtr values to corresponding Haskell functions, one can define a dynamic stub for the specific foreign type, e.g.

 type IntFunction = CInt -> IO ()
 foreign import ccall "dynamic" 
   mkFun :: FunPtr IntFunction -> IntFunction
Constructors
FunPtr Addr#
Instances
IArray UArray (FunPtr a)
Ix ix => Eq (UArray ix (FunPtr a))
Ix ix => Ord (UArray ix (FunPtr a))
MArray (STUArray s) (FunPtr a) (ST s)
IArray (IOToDiffArray IOUArray) (FunPtr a)
MArray IOUArray (FunPtr a) IO
Show (FunPtr a)
Storable (FunPtr a)
Eq (FunPtr a)
Ord (FunPtr a)
Primitive operations
shiftL# :: Word# -> Int# -> Word#
shiftRL# :: Word# -> Int# -> Word#
iShiftL# :: Int# -> Int# -> Int#
iShiftRA# :: Int# -> Int# -> Int#
iShiftRL# :: Int# -> Int# -> Int#
Fusion
build :: forall a . (forall b . (a -> b -> b) -> b -> b) -> [a]
augment :: forall a . (forall b . (a -> b -> b) -> b -> b) -> [a] -> [a]
Linear implicit parameter support
class Splittable t where
Methods
split :: t -> (t, t)
Instances
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