Editing A+ (programming language) (section)

== Features ==

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:
* an A+ function may have up to nine formal parameters
* A+ code statements are separated by semicolons, so a single statement may be divided into two or more physical lines
* The explicit result of a function or operator is the result of the last statement executed
* A+ implements an object called a dependency, which is a global variable (the dependent variable) and an associated definition that is like a function with no arguments. Values can be explicitly set and referenced in exactly the same ways as for a global variable, but they can also be set through the associated definition.

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.