A+ (programming language)
A+ is an array programming language descended from the programming language A, which in turn was created to replace APL in 1988. Arthur Whitney developed the "A" portion of A+, while other developers at Morgan Stanley extended it, adding a graphical user interface and other language features. A+ is a high-level, interactive, interpreted language, designed for numerically intensive applications, especially those found in financial applications. A+ runs on many Unix variants, including Linux. It is free and open source software released under a GNU General Public License. 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 newer graphical user interface 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. 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.