Ada_(programming

{{ infobox programming language
| name = Ada
| logo = [[Image:Ada-cover.jpg|200px]]
| paradigm = [[multi-paradigm programming language|Multi-paradigm]]
| year = 1983, last revised 2005
| designer = [[Jean Ichbiah]], extended by [[S. Tucker Taft]]
| typing = Static, [[Strongly typed programming language|strong]], [[type safety|safe]], [[nominative type system|nominative]]
| implementations = [[GNAT]]
| dialects = Ada 83, Ada 95, Ada 2005
| influenced_by = [[ALGOL 68]], [[Pascal (programming language)|Pascal]], [[C++]] (Ada 95), [[Smalltalk]] (Ada 95), [[Java (programming language)|Java]] (Ada 2005)
| influenced = [[C++]], [[PL/SQL]], [[VHDL]]
}}

'''Ada''' ({{IPAEng|ˈeɪˑdə}}) is a [[structured programming|structured]], [[statically typed]], [[Imperative programming|imperative]], and [[Object-oriented programming|object-oriented]] [[high-level language|high-level]] [[computer programming|computer]] [[programming language]]. It was originally designed by a team led by [[Jean Ichbiah]] of [[Groupe Bull|CII Honeywell Bull]] under contract to the [[United States Department of Defense]] during 1977–1983 to supersede the hundreds of programming languages then used by the [[US Department of Defense]] (DoD). Ada addresses some of the same tasks as [[C (programming language)|C]] or [[C++]], but Ada is [[strongly typed languages|strongly typed]] (even for integer-range), and compilers are validated for reliability in mission-critical applications, such as [[avionics]] software. Ada is an international standard; the current version (known as Ada 2005) is defined by joint ISO/ANSI standard ([http://www.adaic.org/standards/95lrm/html/RM-TTL.html ISO-8652:1995]), combined with major Amendment
[http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=45001 ISO/IEC 8652:1995/Amd 1:2007].

Ada was named after [[Ada Lovelace]] (1815–1852), who is often credited with inventing computer programming.

== Features ==
Ada was originally targeted at [[embedded system|embedded]] and [[real-time computing|real-time]] systems. The Ada 95 revision, designed by [[Tucker Taft|S. Tucker Taft]] of [[Intermetrics]] between 1992 and 1995, improved support for systems, numerical, financial, and [[object-oriented programming]] (OOP).

Notable features of Ada include: [[strongly typed languages|strong typing]], [[modularity (programming)|modularity mechanisms]] (packages), [[run-time checking]], [[parallel processing]] (tasks), [[exception handling]], and [[generic programming|generic]]s. Ada 95 added support for [[object-oriented programming]], including [[dynamic dispatch]].

Ada supports run-time checks in order to protect against access to unallocated memory, [[buffer overflow]] errors, [[off by one errors]], array access errors, and other avoidable bugs. These checks can be disabled in the interest of runtime efficiency, but can often be compiled efficiently. It also includes facilities to help program verification. For these reasons, Ada is widely used in critical systems, where any [[anomaly]] might lead to very serious consequences, i.e., accidental death or injury. Examples of systems where Ada is used include [[avionics]], weapon systems (including [[thermonuclear weapons]]), and [[spacecraft]].

Ada also supports a large number of compile-time checks to help avoid bugs that would not be detectable until run-time in some other languages or would require explicit checks to be added to the source code.

Ada's dynamic [[memory management]] is high-level and type-explicit, requiring explicit instantiation of the Unchecked_Deallocation package to explicitly free allocated memory. The specification does not require any particular implementation. Though the semantics of the language allow automatic [[garbage collection (computer science)|garbage collection]] of inaccessible objects, most implementations do not support it. Ada does support a limited form of [[region-based storage management]]. Invalid accesses can always be detected at run time (unless of course the check is turned off) and sometimes at compile time.

The syntax of Ada is simple, consistent and readable. It minimizes choices of ways to perform basic operations, and prefers English keywords (eg "OR") to symbols (eg. "||"). Ada uses the basic mathematical symbols (i.e.: "+", "-", "*" and "/") for basic mathematical operations but avoids using other symbols. Code blocks are delimited by using words such as "declare", "begin" and "end". It also enforces that each conditional statement be closed. For example, "<tt>'''if''' x > 0 '''then''' y := 0;</tt>" is not valid and must be closed with "end if"; i.e., "<tt>'''if''' x > 0 '''then''' y := 0; '''end if''';</tt>" The rationale is that code for a complex system must be readable by reviewers and maintainers. This was also to avoid the common problem of if-else ambiguity in the grammar. Reviewers may include domain experts who are not highly software literate. Code for complex systems is typically maintained for many years, by programmers other than the original author. It can be argued that these language design principles apply to most software projects, and most phases of software development, however when applied to complex, safety critical projects, benefits in correctness, reliability, and maintainability take precedence over (arguable) costs in initial development.

Unlike most [[International Organization for Standardization|ISO]] standards, the Ada language definition (known as the ''Ada Reference Manual'' or ''ARM'', or sometimes the ''Language Reference Manual'' or ''LRM'') is [[free content]]. Thus, it is a common reference for Ada programmers, not just programmers implementing Ada compilers. Apart from the reference manual, there is also an extensive rationale document which explains the language design and the use of various language constructs. This document is also widely used by programmers. When the language was revised, a new rationale document was written.

== History ==
In the 1970s, the [[United States Department of Defense|US Department of Defense]] (DoD) was concerned by the number of different programming languages being used for its embedded computer system projects, many of which were obsolete or hardware-dependent, and none of which supported safe modular programming. In 1975 the [[Higher Order Language Working Group]] (HOLWG) was formed with the intent of reducing this number by finding or creating a programming language generally suitable for the department's requirements; the result was Ada. The total number of high-level programming languages in use for such projects fell from over 450 in 1983 to 37 by 1996.

{{Wikisource|Steelman language requirements}} The [[working group]] created a series of language requirements documents—the Strawman, Woodenman, Tinman, Ironman and [[Steelman language requirements|Steelman]] documents. Many existing languages were formally reviewed, but the team concluded in 1977 that no existing language met the specifications.

Requests for proposals for a new programming language were issued and four contractors were hired to develop their proposals under the names of Red ([[Intermetrics]] led by [[Benjamin Brosgol]]), Green ([[CII Honeywell Bull]], led by [[Jean Ichbiah]]), Blue ([[SofTech]], led by [http://www.sei.cmu.edu/staff/jbg John Goodenough]), and Yellow ([[SRI International]], led by [[Jay Spitzen]]). In April 1978, after public scrutiny, the Red and Green proposals passed to the next phase. In May of 1979, the Green proposal, designed by Jean Ichbiah at CII Honeywell Bull, was chosen and given the name Ada—after [[Ada Lovelace|Augusta Ada, Countess of Lovelace]]. This proposal was influenced by the programming language [[LIS programming language|LIS]] that Ichbiah and his group had developed in the 1970s. The preliminary Ada reference manual
was published in ACM SIGPLAN Notices in June 1979. The Military Standard reference manual was approved on [[December 10]], [[1980]] ([[Ada Lovelace]]'s birthday), and
given the number MIL-STD-1815 in honor of Ada Lovelace's birth year.

[[Image:Ada Lovelace 1838.jpg|right|caption|thumbnail|157px|[[Ada Lovelace|Augusta Ada King]], Countess of Lovelace.]]
In 1987, the US Department of Defense began to require the use of Ada (the ''Ada mandate'') for every software project where new code was more than 30% of result, though exceptions to this rule were often granted. This requirement was effectively removed in 1997, as the DoD began to embrace COTS ([[commercial off-the-shelf]]) technology. Similar requirements existed in other [[North Atlantic Treaty Organisation|NATO]] countries.

Because Ada is a strongly typed language, it has been used outside the military in commercial aviation projects, where a software bug can mean fatalities. The fly-by-wire system in the [[Boeing 777]] runs software written in Ada. The Canadian Automated Air Traffic System (completed in year 2000 by [http://www.raytheon.ca Raytheon Canada]) was written in 1 million lines of Ada ([[Source lines of code|SLOC]] count). It featured advanced (for the time) distributed processing; a distributed Ada database; and object-oriented design.

The language became an [[American National Standards Institute|ANSI]] standard in 1983 ([http://archive.adaic.com/standards/83lrm/html/Welcome.html ANSI/MIL-STD 1815A]), and without any further changes became
an [[International standard|ISO standard]] in 1987 (ISO-8652:1987). This version of the language is commonly known as Ada 83, from the date of its adoption by ANSI, but is sometimes referred to also as Ada 87, from the date of its adoption by ISO.

Ada 95, the joint ISO/ANSI standard ([http://www.adaic.org/standards/95lrm/html/RM-TTL.html ISO-8652:1995]) is the latest standard for Ada. It was published in February 1995 (making Ada 95 the first ISO standard object-oriented programming language). To help with the standard revision and future acceptance, the [[US Air Force]] funded the development of the [[GNAT]] [[Compiler]]. Presently, the GNAT Compiler is part of the [[GNU Compiler Collection]].

Work has continued on improving and updating the technical content of the Ada programming language. A Technical Corrigendum to Ada 95 was published in October 2001, and a major Amendment, [http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=45001 ISO/IEC 8652:1995/Amd 1:2007], was published on [[March 9]], [[2007]].


== "Hello, world!" in Ada ==
A common example of a language's [[syntax]] is the [[Hello world program]]:
<source lang="ada">
with Ada.Text_IO;

procedure Hello is
begin
Ada.Text_IO.Put_Line("Hello, world!");
end Hello;
</source>

There are shortcuts available for <tt>Ada.Text_IO.Put_Line</tt>, needing less typing; however, they are not used here, for better understanding. For a detailed explanation, see [[Wikibooks:Ada Programming/Basic]].

== See also ==
{{external links}}

=== Online tutorials ===
The following sites have link collections to Ada tutorials:

* [[wikibooks:Programming:Ada:Tutorials|Wikibook tutorial for programming in Ada]]
* [http://www.adapower.com/index.php?Command=Class&ClassID=Tutorials&Title=Tutorials at AdaPower]
* [http://www.adaworld.com/tutorialsmain.html at AdaWorld]
* [http://www.computer-books.us/ada95.php at Computer-Books.us] - A collection of Ada books available for free download.

=== Organizations ===
*[[Ada Information Clearinghouse]]
*[[SIGAda]] - [[Association for Computing Machinery|ACM]] Special Interest Group on Ada
*[[Ada-Europe]] - European organization to promote the use of Ada

=== Compilers ===
* [[AdaMagic]] - Proprietary Ada technology from SofCheck, including Ada 95 front end, run-time system, and tools; front end can generate conventional IL, ISO/ANSI C, or Java byte code
* [[GNAT]] - [[GNAT Modified General Public License|Free]] compiler based on [[GNU Compiler Collection|GCC]]
* [[GNATPro]] - Commercially supported version of [[GNAT]] from AdaCore
* [[JGNAT]] - [[GNAT]]-based compiler for the [[Java Runtime Environment]]
* [[MGNAT]] - [[GNAT]]-based compiler for the [[.NET Framework]] Environment ([[A Sharp (.NET)|A#]] project)
* [[ObjectAda]] - Proprietary Ada compiler from Aonix
* [[PowerAda]] - Proprietary Ada Compiler from OC Systems
* [[AdaMulti]] - Proprietary Ada Compiler and Integrated Development Environment from [[Green Hills Software]]
* SCORE - Proprietary multi language Integrated Development Environment from DDC-I, Inc. including a compiler for Ada as one of its supported languages
* Rational Apex (now owned and sold by IBM) - Proprietary compiler and full IDE

=== Tools ===
{{top}}
* [[A Sharp (.NET)|A#]] (A port of Ada to the Microsoft .NET Platform, [http://asharp.martincarlisle.com/])
* [[Aunit]]
* [[Ada Mode]] (Complete Ada-Mode for Vim, [http://vim.sourceforge.net/scripts/script.php?script_id=1609])
* [[AdaAllegro]] (Ada Interface to Allegro Game Library)
* [[AdaBrowse]] (Javadoc-like HTML generator for Ada 95 library unit specifications, [http://home.tiscalinet.ch/t_wolf/tw/ada95/adabrowse/])
* [[AdaDoc]] ([http://adadoc.sourceforge.net/])
* [[Heybeliada]] ([http://en.wikipedia.org/wiki/Heybeliada/])
* [[AdaCL]] (Ada Class Library, [http://adacl.sourceforge.net/])
* [[AdaGIDE]] (A free GNAT Ada [[Integrated Development Environment]] for Windows)
* [[Ada OpenGL]] ([http://adaopengl.sourceforge.net/])
* [[Cairo bindings for Ada95]] ([http://damien.carbonne.free.fr/download/])
* [[AdaControl]] (ASIS_GNAT the Ada Rule Checker, [http://www.adalog.fr/adacontrol2.htm])
* [[Gnade]] (Ada Database Interface, [http://gnade.sourceforge.net/])
* [[GNAT Programming Studio]] (GPS) AdaCore's complete IDE, available in free and Pro versions
{{mid}}
* [[GNATCOM]] (Ada binding for Microsoft [[Component Object Model|COM]] spec.)
* [[GNAVI]] (Ada Visual RAD)
* [[GtkAda]] (Ada binding for [[GTK+]], [https://libre.adacore.com/GtkAda/])
* [[jGRASP]] (Lightweight development environment with visualizations for improving software comprehensibility, [http://www.jgrasp.org/])
* [[OGLAda]] ([http://www.niestu.com/languages/oglada/])
* [[PolyORB]]
* [[QTAda]] (Older QT bindings for Ada)
* [[QT4ADA]] (QT4 bindings for Ada, [http://qt4ada.sourceforge.net/])
* [[QtAda]] (An Ada2005 language bindings to the Qt libraries, [http://sourceforge.net/projects/qtada/])
* [[SofCheck Inspector]] (Static Error Detection tool, [http://www.sofcheck.com/products/inspector.html])
* [[Tartan Ada]] (Cross compilers for TI TMS320C3x and TMS320C4x DSPs)
* [[TextTools]] (Ncurses-based Mouse-Windows Toolkit for Ada, [http://www.pegasoft.ca/tt.html])
* [[Visual Ada Developer]]
* [[XML-Ada|XML/Ada]] and [[XML4Ada95]]
* [[XIA/XPath In Ada]] (An Ada binding to the [[XPath]] 1.0 spec.)
{{bottom}}
Another list of Ada [[Language binding|bindings]] can be found at [http://www.codeteacher.com/index.php?browse=/Computers/Programming/Languages/Ada/Bindings_and_Libraries/].

=== Related programming languages ===
* [[SPARK programming language|SPARK]] - High integrity language based on an Ada subset
* [[VHDL]] - A hardware description language for representing digital hardware, with many concepts and much syntax borrowed from Ada.
* [[PL/SQL]] - [[Stored procedure]] language in [[Oracle Corporation]]'s [[RDBMS]] product, has many similarities to Ada and was historically based on Ada syntax

=== Others ===
* [[High Integrity System]]s
* [[Ravenscar profile]]
* [[Comparison of programming languages]]

== References ==
<div class="references-small" style="-moz-column-count:2; column-count:2;">
<references />
{{Wikibooks|Ada Programming}}

=== International Standards ===
* [[ISO 8652|ISO/IEC 8652]]: Information technology — Programming languages — Ada
* [[ISO 15291|ISO/IEC 15291]]: Information technology — Programming languages — Ada Semantic Interface Specification ([[wiktionary:ASIS|ASIS]])
* [[ISO 18009|ISO/IEC 18009]]: Information technology — Programming languages — Ada: Conformity assessment of a language processor ([[wiktionary:ACATS|ACATS]])
* [[IEEE 1003|IEEE Standard 1003.5b-1996]], the [[POSIX]] Ada binding
* [http://www.omg.org/technology/documents/formal/ada_language_mapping.htm Ada Language Mapping Specification], the [[CORBA]] [[Interface description language|IDL]] to Ada mapping

=== Rationale ===
(These documents have been published in various forms including print.)

* [http://archive.adaic.com/standards/83rat/html/Welcome.html Jean D. Ichbiah, John G. P. Barnes, Robert J. Firth and Mike Woodger, ''Rationale for the Design of the Ada® Programming Language'', 1986.]
* [http://www.adaic.org/standards/95rat/RAThtml/rat95-contents.html John G. P. Barnes, '' Ada 95 rationale : the language : the standard libraries'', 1995.]
* [http://www.adaic.org/standards/05rat/html/Rat-TTL.html John Barnes, ''Rationale for Ada 2005'', 2005, 2006.]

=== Books ===
* [[Jan Skansholm]]: ''Ada 95 From the Beginning'', Addison-Wesley, ISBN 0-201-40376-5
* [[Geoff Gilpin]]: ''Ada: A Guided Tour and Tutorial'', Prentice hall, ISBN 978-0-13-004045-9
* [[John Barnes (computer scientist)|John Barnes]]: ''Programming in Ada 2005'', Addison-Wesley, ISBN 0-321-34078-7
* [[John Barnes (computer scientist)|John Barnes]]: ''Programming in Ada plus Language Reference Manual'', Addison-Wesley, ISBN 0-201-56539-0
* [[John Barnes (computer scientist)|John Barnes]]: ''Programming in Ada 95'', Addison-Wesley, ISBN 0-201-34293-6
* [[John Barnes (computer scientist)|John Barnes]]: ''High Integrity Ada: The SPARK Approach'', Addison-Wesley, ISBN 0-201-17517-7
* [[John Barnes (computer scientist)|John Barnes]]: ''High Integrity Software: The SPARK Approach to Safety and Security'', Addison-Wesley, ISBN 0-321-13616-0
* [[John Beidler]]: ''Data Structures and Algorithms: An Object-Oriented Approach Using Ada 95'', Springer-Verlag, ISBN 0-387-94834-1
* [[Dean W. Gonzalez]]: ''Ada Programmer's Handbook'', Benjamin-Cummings Publishing Company, ISBN 0-8053-2529-8
* [[M. Ben-Ari]]: ''Ada for Software Engineers'', John Wiley & Sons, ISBN 0-471-97912-0
* [[Norman Cohen]]: ''Ada as a Second Language'', McGraw-Hill Science/Engineering/Math, ISBN 0-07-011607-5
* [[Alan Burns]], [[Andy Wellings]]: ''Real-Time Systems and Programming Languages. Ada 95, Real-Time Java and Real-Time POSIX.'', Addison-Wesley, ISBN 0-201-72988-1
* [[Alan Burns]], [[Andy Wellings]]: ''Concurrency in Ada'', Cambridge University Press, ISBN 0-521-62911-X
* [[Colin Atkinson]]: ''Object-Oriented Reuse, Concurrency and Distribution: An Ada-Based Approach'', Addison-Wesley, ISBN 0-201-56527-7
* [[Grady Booch]], [[Doug Bryan]]: ''Software Engineering with Ada'', Addison-Wesley, ISBN 0-8053-0608-0
* [[Daniel Stubbs]], [[Neil W. Webre]]: ''Data Structures with Abstract Data Types and Ada'', Brooks Cole, ISBN 0-534-14448-9
* [[Pascal Ledru]]: ''Distributed Programming in Ada with Protected Objects'', Dissertation.com, ISBN 1-58112-034-6
* [[Fintan Culwin]]: ''Ada, a Developmental Approach'', Prentice Hall, ISBN 0-13-264680-3
* [[John English]], [[Fintan Culwin]]: ''Ada 95 the Craft of Object Oriented Programming'', Prentice Hall, ISBN 0-13-230350-7
* [[David A. Wheeler]]: ''Ada 95'', Springer-Verlag, ISBN 0-387-94801-5
* [[David R. Musser]], [[Alexander Stepanov]]: ''The Ada Generic Library: Linear List Processing Packages'', Springer-Verlag, ISBN 0-387-97133-5
* [[Michael B. Feldman]]: ''Software Construction and Data Structures with Ada 95'', Addison-Wesley, ISBN 0-201-88795-9
* [[Simon Johnston]]: ''Ada 95 for C and C++ Programmers'', Addison-Wesley, ISBN 0-201-40363-3
*[[Michael B. Feldman]], [[Elliot B. Koffman]]: ''Ada 95'', Addison-Wesley, ISBN 0-201-36123-X
* [[Nell Dale]], [[Chip Weems]], John McCormick: ''Programming and Problem Solving with Ada 95'', Jones & Bartlett Publishers, ISBN 0-7637-0293-5
* [[Nell Dale]], [[John McCormick]]: ''Ada Plus Data Structures: An Object-Oriented Approach, 2nd edition'', Jones & Bartlett Publishers, ISBN 0-7637-3794-1
* [[Bruce C. Krell]]: ''Developing With Ada: Life-Cycle Methods'', Bantam Dell Pub Group, ISBN 0-553-09102-6
* [[Judy Bishop]]: ''Distributed Ada: Developments and Experiences'', Cambridge University Press, ISBN 0-521-39251-9
* [[Bo Sanden]]: ''Software Systems Construction With Examples in Ada'', Prentice Hall, ISBN 0-13-030834-X
* [[Bruce Hillam]]: ''Introduction to Abstract Data Types Using Ada'', Prentice Hall, ISBN 0-13-045949-6
* [[David Rudd]]: ''Introduction to Software Design and Development With Ada'', Brooks Cole, ISBN 0-314-02829-3
* [[Ian C. Pyle]]: ''Developing Safety Systems: A Guide Using Ada'', Prentice Hall, ISBN 0-13-204298-3
* [[Louis Baker]]: ''Artificial Intelligence With Ada'', McGraw-Hill, ISBN 0-07-003350-1
* [[Alan Burns]], [[Andy Wellings]]: ''HRT-HOOD: A Structured Design Method for Hard Real-Time Ada Systems'', North-Holland, ISBN 0-444-82164-3
* [[Walter Savitch, Charles Peterson]]: ''Ada: An Introduction to the Art and Science of Programming'', Benjamin-Cummings Publishing Company, ISBN 0-8053-7070-6
* [[Mark Allen Weiss]]: ''Data Structures and Algorithm Analysis in Ada'', Benjamin-Cummings Publishing Company, ISBN 0-8053-9055-3
* [[Henry Ledgard]]: ''ADA: AN INTRODUCTION (Second Edition)'', Springer-Verlag, ISBN 0-387-90814-5

=== Archives ===
* [http://special.lib.umn.edu/findaid/xml/cbi00157.xml Ada Programming Language Materials, 1981-1990]. Charles Babbage Institute, University of Minnesota, Minneapolis.
</div>

== External links ==

* {{dmoz|Computers/Programming/Languages/Ada/|Ada programming language}}
* [http://www.sigada.org/ ACM SIGAda]
* [http://www.ada-europe.org/ Ada-Europe Organization]
* [http://www.open-std.org/jtc1/sc22/wg9/ ISO Home of Ada Standards]

[[Category:.NET programming languages]]
[[Category:Ada programming language|*Ada]]
[[Category:Algol programming language family]]
[[Category:Concurrent programming languages]]
[[Category:Computer and telecommunication standards]]
[[Category:Procedural programming languages]]
[[Category:Multi-paradigm programming languages]]
[[Category:Object-oriented programming languages]]
[[Category:Programming languages]]
[[Category:Statically-typed programming languages]]
[[Category:Systems programming languages]]

[[ar:أدا]]
[[an:Lenguache de programazión Ada]]
[[bn:অ্যাডা]]
[[bg:Ada]]
[[ca:Ada]]
[[cs:Ada]]
[[da:Ada (programmeringssprog)]]
[[de:Ada (Programmiersprache)]]
[[el:Ada]]
[[es:Lenguaje de programación Ada]]
[[fa:ایدا]]
[[fr:Ada (langage)]]
[[gl:Ada]]
[[ko:에이다]]
[[id:Ada (bahasa pemrograman)]]
[[he:עדה (שפת תכנות)]]
[[hu:Ada (programozási nyelv)]]
[[nl:Ada (programmeertaal)]]
[[ja:Ada]]
[[no:Ada]]
[[nn:Programmeringsspråket Ada]]
[[pl:Ada (informatyka)]]
[[pt:Ada (linguagem de programação)]]
[[ru:Ада (язык программирования)]]
[[sk:Ada (programovací jazyk)]]
[[sl:Ada (programski jezik)]]
[[fi:Ada]]
[[sv:Ada (programspråk)]]
[[th:ภาษาเอดา]]
[[vi:Ada (ngôn ngữ lập trình)]]
[[tg:Ада (забони барноманависӣ)]]
[[tr:Ada programlama dili]]
[[uk:Ada]]
[[zh:Ada]]