Ada (language)

Presentation

Ada is a Computer programming language conceived by the team of CII-Honeywell Bull directed by Jean Ichbiah in answer to a schedule of conditions established by the American Department of Defense (DoD). Its development started at the beginning of the Années 1980 to give Ada 83 .

It was then taken again and improve in the middle of the Années 1990 to give Ada 95 , the first standardized object language in an international way. Under the auspices of the International organization of standardization (ISO), the language now lays out of a called minor revision Ada 2005 .

The name Ada was selected in the honor of Ada Lovelace, which is supposed to have written the first program of the history. It is associated with the green color because, at the time of the invitation to tender of DoD, the various proposals were indicated by colors to avoid any skew, and equips it which conceived it was the green team.

Here some characteristics of Ada:

static Typing,
module by parcellings and controls fine visibility
Syntaxe clear and nonambiguous (inspired by that of the language PASCAL),
Généricité,
milked real-time integrated into the language (protected tasks, objects, interruptions),
standardized libraries, bonds with the other languages,
additional time-reality with the Profil Ravenscar for the sure systems,

It is often used in systems embarked real-time and requiring an high level of reliability and safety.

Currently (2006), it is possible to very find Compilateur S Ada of good quality for all kinds of operating systems (Windows, Linux, VxWorks) and architectures, including a free compiler (GNAT, included in GNU Compiler Collection ) compiling of Ada 83/95 (like some aspects of Ada 2005, especially its notation object, but without beings in conformity with Ada 2005, although that is sometimes alleged by short cut).

Ada is often used in introduction to the courses of advanced Programmation, and because it shares same teaching qualities as the Pascal (which it inherited), Ada is even now used for the courses of introduction to the Programmation.

Other languages in Ada mobility

Ada is inspired by the Pascal of which it took again the spirit of syntax as well as architecture (especially if one includes Turbo Pascal). The Ada language inspired Bertrand Meyer for the design of the language Eiffel, which adds to it concepts of programming by contracts (but shows itself less adapted to industry under certain aspects). The concept of Programming by constraint formalized, by Bertrand Meyer with Eiffel, brought the creation of a project of extension of Ada, to make him support notations making it possible to express contractual assertions in the specifications of package (these extensions function like a surcouche, and are treated by a preprocessor).

" Hello, world! " in Ada 95 or Ada 2005

An example running to show the syntax of a language is the program Hello world: with Ada.Text_IO; --library

procedure Hello is -- Procedure " announces; Hello" begin -- Beginning of the procedure " Hello" Ada.Text_IO.Put_Line (" Hello, world! "); -- Code which prints Hello, world! with the screen end Hello; --End of the procedure " Hello"

There exist short cuts for Ada.Text_IO.Put_Line requiring less characters, but they are not used here for reasons of comprehension. For more detailed explanations, you can consult Wikibooks: Ada Programming/BASIC.

Short history

1974 - the American Department of Defense realizes that it enormously wastes money by using roughly speaking a Computer programming language by application, and while maintaining the programs written in endemic or exotic obsolete languages. Certain sources advance the figure of 500 computer programming languages employed in these places.

The result of this awakening is the development, in 3 years, of the schedule of conditions of a single language, sufficiently flexible and powerful to replace all the others, that it is for the guidance of missile or work on the Artificial intelligence while passing by the business applications.

1977 - the department launches an invitation to tender, gained by a team directed by the French Jean Ichbiah.

1983 - Ada83 is standardized with the the United States by ANSI (ANSI/MIL-STD-1815A-1983).

1987 - Ada83 is the subject of the International standard ISO 8652:1987.

1990 - Starting from the improvements made by the various developers of compilers, Ada Joint Program Office launches a project of revision of the language.

1992 - a contract signed between the committee of revision (Ada9X Program Office) and the Université of New York for the development of a compiler of reference for the new language, which will be freely available. This compiler, GNAT, are based on technology GCC of GNU.

1994 - the company Ada Core Technologies (today AdaCore) is rested by the members of the project GNAT to continue the maintenance of the compiler and to ensure marketing and the support of it.

1995 - the so much awaited revision comes to a end, Ada95 is born. A revised standard is published, ISO/CEI 8652:1995. Ada95 is the first language which implements the Programmation directed object to be the subject of an international standard. The compiler GNAT covers the entirety of the Ada95 standard, including the whole of its appendices optional.

2000 - the Ada Conformity Assessment Authority (ACAA) publishes a whole of minor corrections accumulated during the five previous years: Technical Corrigendum 1.

2004 - Nowadays, Ada95 is employed of course by its initiator, but also in all state-of-the-art technologies; in France, the car, rail-bound transports (ALSTOM, Matra, CSEE) (TGV, Coral, the RER, METEOR), aeronautical technologies (Thales Air Defense, Thalès Avionics, Airbus) and space technologies (Alcatel Space, CNES, Arianespace).

2005 - an amendment to the standard is in preparation within the ISO work group responsible for the Ada standards. This introduced amendment of new functionalities and officializes many improvements suggested initially by the various developers of compilers. The revision of the language is officially adopted and bears the name Ada 2005.

Internal bond

GNAT (free Ada compiler)

External bonds

Ada France: this association organizes a contest every year with high prices (1500 € for the first price).
Develop: Various resources on Ada.
Lea-Linux: Introduction to the Ada language.
free pages of AdaCore: AdaCore proposes here in remote loading its tools LPG in particular compiler GNAT and the environment of development GPS.
Ada Confirmity Assessment Authority : this independent group supervises the checking of conformity of the implementations of the language (formerly called “validation”) and pilot the process of amendment and improvement of the definition of the language.
Ada Programming/Ada 2005 : A work freely available on the new amendment to the standard.

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