Editing A+ (programming language)

{{Short description|Programming language}}
{{Notability|1=Web|date=April 2024}}
{{Primary sources|date=February 2023}}
{{Infobox programming language
|name = A+
|logo = Aplus logo.jpg
|paradigm = [[Array programming|Array]]
|designer = [[Arthur Whitney (computer scientist)|Arthur Whitney]]
|developer = [[Morgan Stanley]]
|released = A – {{Start date and age|1985}}<br/>A+ – {{Start date and age|1988}}
|latest release version = 4.22-1
|latest release date = {{Start date and age|2008|03|27}}
|typing = [[Dynamic typing|Dynamic]], [[strong typing|strong]]
|file_ext = {{mono|..}}, {{mono|.+}}, {{mono|.a}}, {{mono|.m}}<ref>{{cite web|url=http://www.aplusdev.org/APlusRefV2_63.html#HEADING991|title=A+ Reference: Appendix: Quick Reference|access-date=2020-02-06|archive-date=2020-02-24|archive-url=https://web.archive.org/web/20200224202643/http://www.aplusdev.org/APlusRefV2_63.html#HEADING991|url-status=dead}}</ref>
|implementations = A+
|dialects =
|influenced by = [[APL (programming language)|APL]]
|influenced = [[K (programming language)|K]]
|license=[[GNU General Public License]]
}}

'''A+''' is a high-level, interactive, [[interpreted language|interpreted]] [[array programming language]] designed for numerically intensive applications, especially those found in financial applications.

== History ==

In 1985, [[Arthur Whitney (computer scientist)|Arthur Whitney]] created the A programming language<ref>{{Cite web |url=https://aplwiki.com/wiki/A |title=A – APL Wiki}}</ref> to replace [[APL (programming language)|APL]].<ref>{{Cite web |url=http://www.aplusdev.org/About/ |archive-url=https://web.archive.org/web/20020619011949/http://aplusdev.org/About/ |url-status=dead |archive-date=June 19, 2002 |title=A+: History of A+ |website=www.aplusdev.org |access-date=2019-01-18}}</ref> 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 (computer scientist)|Arthur Whitney]] went on to create a proprietary array language named [[K (programming language)|K]]. Like [[J (programming language)|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 (programming languages)|syntax]].

== 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.

==References==
{{Reflist}}

==External links==
*{{Official website|www.aplusdev.org}}{{Dead link|date=November 2023}}, aplusdev.org

{{APL programming language}}

[[Category: APL programming language family]]
[[Category: Array programming languages]]
[[Category: Data-centric programming languages]]