Data.Array.Vanilla.Unsafe

Two flavours of array: mutable and immutable. All are boxed, lazy, and use zero-origin integers as indicies.

Documentation

data IArray x

The type of immutable arrays, with elements of type x.

data MArray s x

The type of mutable arrays, with elements of type x. These arrays live in the ST monad, but you can use stToIO to convert this to IO if required.

Two MArrays are equal as per (==) if they are both the exact same array (i.e., the same block of RAM). Two seperate arrays which merely hold the same data are not considered equal. (This fact could change at any second, after all.)

Instances

Eq (MArray s x)

marray_new :: Int -> x -> ST s (MArray s x)

Create a brand new MArray, of the specified size, with all elements set to the value provided. If the array size is n, valid indicies are from 0 to n-1.

marray_read :: MArray s x -> Int -> ST s x

Read from an MArray.

Unsafe: No bounds checks. Indicies below 0 or above n-1 will likely result in a program crash.

marray_write :: MArray s x -> Int -> x -> ST s ()

Write to an MArray, replacing the element at the specified index.

Unsafe: No bounds checks. Indicies below 0 or above n-1 will likely result in a program crash (if you're lucky), or weird data corruption (if you're unlucky).

marray_freeze :: MArray s x -> ST s (IArray x)

Create a new IArray which refers to the same memory block as an existing MArray.

Unsafe: Mutating the MArray will cause the contents of the IArray to mutate also, violating referential transparency. (Avoid this by explicitly copying the data before freezing.)

iarray_thaw :: IArray x -> ST s (MArray s x)

Create a new MArray which refers to the same memory block as an existing IArray.

Unsafe: Mutating the MArray will cause the contents of the IArray to mutate also, violating referential transparency. (Avoid this by explicitly copying the data after thawing and before mutating it.)

iarray_read :: IArray x -> Int -> x

Read from an IArray. (Since IArrays are immutable, this is a pure operation.)

Unsafe: No bounds checks. Indicies below 0 or above n-1 will likely result in a program crash.