| A+ | |
| Paradigm: | Array |
| Designer: | Arthur Whitney |
| Developer: | Morgan Stanley |
| Released: | A – A+ – |
| Latest Release Version: | 4.22-1 |
| Typing: | Dynamic, strong |
| File Ext: | ,,, [1] |
| Implementations: | A+ |
| Influenced By: | APL |
| Influenced: | K |
| License: | GNU General Public License |
A+ is a high-level, interactive, interpreted array programming language designed for numerically intensive applications, especially those found in financial applications.
In 1985, Arthur Whitney created the A programming language[2] to replace APL.[3] Other developers at Morgan Stanley extended it to A+, adding a graphical user interface (GUI) and other language features. The GUI A+ was released in 1988.
Arthur Whitney went on to create a proprietary array language named K. Like J, K omits the APL character set. It lacks some of the perceived complexities of A+, such as the existence of statements and two different modes of syntax.
A+ provides an extended set of functions and operators, a graphical user interface with automatic synchronizing of widgets and variables, asynchronous executing of functions associated with variables and events, dynamic loading of user compiled subroutines, and other features. A+ runs on many Unix variants, including Linux. It is free and open source software released under a GNU General Public License. A newer GUI has not yet been ported to all supported platforms.
The A+ language implements the following changes to the APL language:
Interactive A+ development is primarily done in the Xemacs editor, through extensions to the editor. Because A+ code uses the original APL symbols, displaying A+ requires a font with those special characters; a font named kapl is provided on the web site for that purpose.