Comparison of programming languages (associative array): Difference between revisions

Revision as of 18:26, 21 March 2021

Revision as of 20:09, 1 May 2021

Line 1,818:

The SML'97 standard of the [[Standard ML]] programming language does not provide any associative containers. However, various implementations of Standard ML do provide associative containers.

The library of the popular [[Standard ML of New Jersey]] (SML/NJ) implementation provides a signature (somewhat like an "interface"), <code>ORD_MAP</code>, which defines a common interface for ordered functional (immutable) associative arrays. There are several general functors—<code>BinaryMapFn</code>, <code>ListMapFn</code>, <code>RedBlackMapFn</code>, and <code>SplayMapFn</code>—that allow you to create the corresponding type of ordered map (the types are a [[self-balancing binary search tree]], sorted [[association list]], [[red-blackred–black tree]], and [[splay tree]], respectively) using a user-provided structure to describe the key type and comparator. The functor returns a structure in accordance with the <code>ORD_MAP</code> interface. In addition, there are two pre-defined modules for associative arrays that employ integer keys: <code>IntBinaryMap</code> and <code>IntListMap</code>.

<syntaxhighlight lang="sml">