Data.Array.ST

Mutable boxed and unboxed arrays in the ST monad.

Boxed arrays

data STArray s i e

Mutable, boxed, non-strict arrays in the ST monad. The type arguments are as follows:

• s: the state variable argument for the ST type
• i: the index type of the array (should be an instance of Ix)
• e: the element type of the array.

Instances

Typeable3 STArray

MArray (STArray s) e (ST s)

MArray (STArray s) e (ST s)

Eq (STArray s i e)

runSTArray :: Ix i => (forall s. ST s (STArray s i e)) -> Array i e

A safe way to create and work with a mutable array before returning an immutable array for later perusal. This function avoids copying the array before returning it - it uses unsafeFreeze internally, but this wrapper is a safe interface to that function.

Unboxed arrays

data STUArray s i e

A mutable array with unboxed elements, that can be manipulated in the ST monad. The type arguments are as follows:

• s: the state variable argument for the ST type
• i: the index type of the array (should be an instance of Ix)
• e: the element type of the array. Only certain element types are supported.

An STUArray will generally be more efficient (in terms of both time and space) than the equivalent boxed version (STArray) with the same element type. However, STUArray is strict in its elements - so don't use STUArray if you require the non-strictness that STArray provides.

Instances

Typeable3 STUArray

MArray (STUArray s) Word64 (ST s)

MArray (STUArray s) Word32 (ST s)

MArray (STUArray s) Word16 (ST s)

MArray (STUArray s) Word8 (ST s)

MArray (STUArray s) Int64 (ST s)

MArray (STUArray s) Int32 (ST s)

MArray (STUArray s) Int16 (ST s)

MArray (STUArray s) Int8 (ST s)

MArray (STUArray s) Double (ST s)

MArray (STUArray s) Float (ST s)

MArray (STUArray s) Word (ST s)

MArray (STUArray s) Int (ST s)

MArray (STUArray s) Char (ST s)

MArray (STUArray s) Bool (ST s)

MArray (STUArray s) (StablePtr a) (ST s)

MArray (STUArray s) (FunPtr a) (ST s)

MArray (STUArray s) (Ptr a) (ST s)

Eq (STUArray s i e)

runSTUArray :: Ix i => (forall s. ST s (STUArray s i e)) -> UArray i e

A safe way to create and work with an unboxed mutable array before returning an immutable array for later perusal. This function avoids copying the array before returning it - it uses unsafeFreeze internally, but this wrapper is a safe interface to that function.

castSTUArray :: STUArray s ix a -> ST s (STUArray s ix b)

Casts an STUArray with one element type into one with a different element type. All the elements of the resulting array are undefined (unless you know what you're doing...).

Overloaded mutable array interface

module Data.Array.MArray