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.
Single-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE single-precision type.
Double-precision floating point numbers. It is desirable that this type be at least equal in range and precision to the IEEE double-precision type.
The character type Char
is an enumeration whose values represent Unicode (or equivalently ISO/IEC 10646) characters (see http://www.unicode.org/ for details). This set extends the ISO 8859-1 (Latin-1) character set (the first 256 characters), 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
).
A value of type
represents a pointer to an object, or an array of objects, which may be marshalled to or from Haskell values of type Ptr
aa
.
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
.
A value of type
is a pointer to a function callable from foreign code. The type FunPtr
aa
will normally be a foreign type, a function type with zero or more arguments where
Char
, Int
, Double
, Float
, Bool
, Int8
, Int16
, Int32
, Int64
, Word8
, Word16
, Word32
, Word64
, Ptr
a
, FunPtr
a
, StablePtr
a
or a renaming of any of these using newtype
.IO
t
where t
is a marshallable foreign type or ()
.A value of type
may be a pointer to a foreign function, either returned by another foreign function or imported with a a static address import likeFunPtr
a
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 -> IntFunctionThe maximum tuple size Primitive operations
module GHC.Prim
iShiftRA# :: Int# -> Int# -> Int#Source
Shift the argument right (signed) by the specified number of bits (which must be non-negative).
iShiftRL# :: Int# -> Int# -> Int#Source
Shift the argument right (unsigned) by the specified number of bits (which must be non-negative).
uncheckedShiftL64# :: Word# -> Int# -> Word#Source
uncheckedShiftRL64# :: Word# -> Int# -> Word#Source
uncheckedIShiftL64# :: Int# -> Int# -> Int#Source
uncheckedIShiftRA64# :: Int# -> Int# -> Int#Source
Fusionbuild :: forall a. (forall b. (a -> b -> b) -> b -> b) -> [a]Source
A list producer that can be fused with foldr
. This function is merely
build g = g (:) []
but GHC's simplifier will transform an expression of the form
, which may arise after inlining, to foldr
k z (build
g)g k z
, which avoids producing an intermediate list.
augment :: forall a. (forall b. (a -> b -> b) -> b -> b) -> [a] -> [a]Source
A list producer that can be fused with foldr
. This function is merely
augment g xs = g (:) xs
but GHC's simplifier will transform an expression of the form
, which may arise after inlining, to foldr
k z (augment
g xs)g k (
, which avoids producing an intermediate list.foldr
k z xs)
Class for string-like datastructures; used by the overloaded string extension (-foverloaded-strings in GHC).
Debuggingbreakpoint :: a -> aSource
breakpointCond :: Bool -> a -> aSource
Ids with special behaviourThe call '(lazy e)' means the same as e
, but lazy
has a magical strictness property: it is lazy in its first argument, even though its semantics is strict.
The call '(inline f)' reduces to f
, but inline
has a BuiltInRule that tries to inline f
(if it has an unfolding) unconditionally The NOINLINE
pragma arranges that inline only gets inlined (and hence eliminated) late in compilation, after the rule has had a good chance to fire.
The Down
type allows you to reverse sort order conveniently. A value of type
contains a value of type Down
aa
(represented as
). If Down
aa
has an
instance associated with it then comparing two values thus wrapped will give you the opposite of their normal sort order. This is particularly useful when sorting in generalised list comprehensions, as in: Ord
then sortWith by
Down
x
groupWith :: Ord b => (a -> b) -> [a] -> [[a]]Source
The groupWith
function uses the user supplied function which projects an element out of every list element in order to first sort the input list and then to form groups by equality on these projected elements
sortWith :: Ord b => (a -> b) -> [a] -> [a]Source
The sortWith
function sorts a list of elements using the user supplied function to project something out of each element
the
ensures that all the elements of the list are identical and then returns that unique element
currentCallStack :: IO [String]Source
returns a '[String]' representing the current call stack. This can be useful for debugging.
The implementation uses the call-stack simulation maintined by the profiler, so it only works if the program was compiled with -prof
and contains suitable SCC annotations (e.g. by using -fprof-auto
). Otherwise, the list returned is likely to be empty or uninformative.
data Constraint Source
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