Standard ML of New Jersey

The UNSAFE_MONO_VECTOR signature

Synopsis

signature UNSAFE_MONO_VECTOR


For those of you that don't mind a little insecurity if only your vector accesses don't have bounds checks, here are some unchecked operations on vectors.

These operations work on ordinary vectors, so you can mix checked and unchecked operations on the same vectors.

In an ideal world (which we're working on, in principle) the compiler would let you use the ordinary checked operations and then optimize the checks away in a safe and efficient manner.

Interface

type vector
type elem
val sub : (vector * int) -> elem
val update : (vector * int * elem) -> unit
val create : int -> vector


Description

type vector

type elem

sub (vec, i)

Fetch the ith element of a. If i is negative or greater than or equal to the length of a, the results will be unpredictable and may corrupt the further execution of the ML program.

update (vec, i, el)

Store x into the ith element of a. If i is negative or greater than or equal to the length of a, the results will be unpredictable and may corrupt the further execution of the ML program.

This operation is particularly unsafe, even if i is in range, because the compiler performs other optimizations on vectors based on the fact that their contents are immutable.

create i

Create an array of i elements, with every slot uninitialized. If i is negative or greater than the largest array size that the system can represent the results will be unpredictable and may corrupt the further execution of the ML program.

See Also

MONO_VECTOR, UNSAFE_MONO_ARRAY, Unsafe.Vector

Last Modified October 28, 1997
Comments to sml-nj@research.bell-labs.com
Copyright © 1998 Bell Labs, Lucent Technologies