Data.Array.MArray.Safe

Class of mutable array types.

An array type has the form (a i e) where a is the array type constructor (kind * -> * -> *), i is the index type (a member of the class Ix), and e is the element type.

The MArray class is parameterised over both a and e (so that instances specialised to certain element types can be defined, in the same way as for IArray), and also over the type of the monad, m, in which the mutable array will be manipulated.

The Ix class is used to map a contiguous subrange of values in a type onto integers. It is used primarily for array indexing (see the array package).

The first argument (l,u) of each of these operations is a pair specifying the lower and upper bounds of a contiguous subrange of values.

An implementation is entitled to assume the following laws about these operations:

• inRange (l,u) i == elem i (range (l,u))

• range (l,u) !! index (l,u) i == i, when inRange (l,u) i

• map (index (l,u)) (range (l,u))) == [0..rangeSize (l,u)-1]

• rangeSize (l,u) == length (range (l,u))

Builds a new array, with every element initialised to the supplied value. The first and second element of the tuple specifies the lowest and highest index, respectively.

Builds a new array, with every element initialised to an undefined value. In a monadic context in which operations must be deterministic (e.g. the ST monad), the array elements are initialised to a fixed but undefined value, such as zero. The first and second element of the tuple specifies the lowest and highest index, respectively.

Constructs a mutable array from a list of initial elements. The list gives the elements of the array in ascending order beginning with the lowest index. The first and second element of the tuple specifies the lowest and highest index, respectively.

Constructs a mutable array using a generator function. It invokes the generator function in ascending order of the indices.

Read an element from a mutable array

Write an element in a mutable array

Strict accumulating left-associative fold.

Strict accumulating right-associative fold.

Map elements to monadic actions, sequence them left-to-right, and discard the results.

forMArrayM_ is mapMArrayM_ with its arguments flipped.

Strict accumulating left-associative monadic fold.

Strict accumulating right-associative monadic fold.

Constructs a new array derived from the original array by applying a function to each of the elements.

Constructs a new array derived from the original array by applying a function to each of the indices.

Returns the bounds of the array (lowest,highest).

Return a list of all the elements of a mutable array

Return a list of all the associations of a mutable array, in index order.

Converts a mutable array (any instance of MArray) to an immutable array (any instance of IArray) by taking a complete copy of it.

Converts an immutable array (any instance of IArray) into a mutable array (any instance of MArray) by taking a complete copy of it.