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Ada (programming language)

Ada is a structured, statically typed, imperative, and object-oriented high-level programming language, inspired by Pascal and other languages. It has built-in language support for design by contract (DbC), extremely strong typing, explicit concurrency, tasks, synchronous message passing, protected objects, and non-determinism. Ada improves code safety and maintainability by using the compiler to find errors in favor of runtime errors. Ada is an international technical standard, jointly defined by the International Organization for Standardization (ISO), and the International Electrotechnical Commission (IEC). As of May 2023, the standard, called Ada 2022 informally, is ISO/IEC 8652:2023.[11]

Ada
ParadigmMulti-paradigm: structured, imperative, object-oriented, aspect-oriented,[1] concurrent, array, distributed, generic, procedural, meta
FamilyPascal
Designed by
  • MIL-STD-1815, Ada 83: Jean Ichbiah
  • Ada 95: Tucker Taft
  • Ada 2005: Tucker Taft
  • Ada 2012: Tucker Taft
First appearedFebruary 1980; 44 years ago (1980-02)
Stable release
Ada 2022 / May 2023
Typing disciplinestatic, strong, safe, nominal
OSMulti- or cross-platform
Filename extensions.adb, .ads
Websiteada-lang.io
Major implementations
AdaCore GNAT,[2]
Green Hills Software Optimising Ada 95 compiler,
PTC ApexAda and ObjectAda,[3]
MapuSoft Ada-C/C++ changer,[4] formerly known as "AdaMagic with C Intermediate",[5]
DDC-I Score
Dialects
SPARK, Ravenscar profile
Influenced by
ALGOL 68, Pascal, Simula 67,[6] C++ (Ada 95), Smalltalk (Ada 95), Modula-2 (Ada 95) Java (Ada 2005), Eiffel (Ada 2012)
Influenced
C++, Chapel,[7] Drago,[8] D, Eiffel, Griffin,[9] Java, Nim, ParaSail, PL/SQL, PL/pgSQL, Python, Ruby, Seed7, SPARforte,[10] Sparkel, SQL/PSM, VHDL
  • Ada Programming at Wikibooks

Ada was originally designed by a team led by French computer scientist Jean Ichbiah of Honeywell under contract to the United States Department of Defense (DoD) from 1977 to 1983 to supersede over 450 programming languages used by the DoD at that time.[12] Ada was named after Ada Lovelace (1815–1852), who has been credited as the first computer programmer.[13]

Features edit

Ada was originally designed for embedded and real-time systems. The Ada 95 revision, designed by S. Tucker Taft of Intermetrics between 1992 and 1995, improved support for systems, numerical, financial, and object-oriented programming (OOP).

Features of Ada include: strong typing, modular programming mechanisms (packages), run-time checking, parallel processing (tasks, synchronous message passing, protected objects, and nondeterministic select statements), exception handling, and generics. Ada 95 added support for object-oriented programming, including dynamic dispatch.

The syntax of Ada minimizes choices of ways to perform basic operations, and prefers English keywords (such as "or else" and "and then") to symbols (such as "||" and "&&"). Ada uses the basic arithmetical operators "+", "-", "*", and "/", but avoids using other symbols. Code blocks are delimited by words such as "declare", "begin", and "end", where the "end" (in most cases) is followed by the identifier of the block it closes (e.g., if ... end if, loop ... end loop). In the case of conditional blocks this avoids a dangling else that could pair with the wrong nested if-expression in other languages like C or Java.

Ada is designed for developing very large software systems. Ada packages can be compiled separately. Ada package specifications (the package interface) can also be compiled separately without the implementation to check for consistency. This makes it possible to detect problems early during the design phase, before implementation starts.

A large number of compile-time checks are supported 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. For example, the syntax requires explicitly named closing of blocks to prevent errors due to mismatched end tokens. The adherence to strong typing allows detecting many common software errors (wrong parameters, range violations, invalid references, mismatched types, etc.) either during compile-time, or otherwise during run-time. As concurrency is part of the language specification, the compiler can in some cases detect potential deadlocks.[14] Compilers also commonly check for misspelled identifiers, visibility of packages, redundant declarations, etc. and can provide warnings and useful suggestions on how to fix the error.

Ada also supports run-time checks to protect against access to unallocated memory, buffer overflow errors, range violations, off-by-one errors, array access errors, and other detectable 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 sometimes used in critical systems, where any anomaly might lead to very serious consequences, e.g., accidental death, injury or severe financial loss. Examples of systems where Ada is used include avionics, air traffic control, railways, banking, military and space technology.[15][16]

Ada's dynamic memory management is high-level and type-safe. Ada has no generic or untyped pointers; nor does it implicitly declare any pointer type. Instead, all dynamic memory allocation and deallocation must occur via explicitly declared access types. Each access type has an associated storage pool that handles the low-level details of memory management; the programmer can either use the default storage pool or define new ones (this is particularly relevant for Non-Uniform Memory Access). It is even possible to declare several different access types that all designate the same type but use different storage pools. Also, the language provides for accessibility checks, both at compile time and at run time, that ensures that an access value cannot outlive the type of the object it points to.[17]

Though the semantics of the language allow automatic garbage collection of inaccessible objects, most implementations do not support it by default, as it would cause unpredictable behaviour in real-time systems. Ada does support a limited form of region-based memory management; also, creative use of storage pools can provide for a limited form of automatic garbage collection, since destroying a storage pool also destroys all the objects in the pool.

A double-dash ("--"), resembling an em dash, denotes comment text. Comments stop at end of line; there is intentionally no way to make a comment span multiple lines, to prevent unclosed comments from accidentally voiding whole sections of source code. Disabling a whole block of code therefore requires the prefixing of each line (or column) individually with "--". While this clearly denotes disabled code by creating a column of repeated "--" down the page, it also renders the experimental dis/re-enablement of large blocks a more drawn-out process in editors without block commenting support.

The semicolon (";") is a statement terminator, and the null or no-operation statement is null;. A single ; without a statement to terminate is not allowed.

Unlike most 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 only 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.

One notable free software tool that is used by many Ada programmers to aid them in writing Ada source code is the GNAT Programming Studio, and GNAT which is part of the GNU Compiler Collection.

History edit

In the 1970s the US Department of Defense (DoD) became 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, a working group, the High Order Language Working Group (HOLWG), was formed with the intent to reduce this number by finding or creating a programming language generally suitable for the department's and the UK Ministry of Defence's requirements. After many iterations beginning with an original straw-man proposal[18] the eventual programming language was named Ada. The total number of high-level programming languages in use for such projects fell from over 450 in 1983 to 37 by 1996.

HOLWG crafted the Steelman language requirements, a series of documents stating the requirements they felt a programming language should satisfy. Many existing languages were formally reviewed, but the team concluded in 1977 that no existing language met the specifications.

 
Watercolour painting of Ada Lovelace

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 (Honeywell, led by Jean Ichbiah), Blue (SofTech, led by John Goodenough)[19] 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 1979, the Green proposal, designed by Jean Ichbiah at Honeywell, was chosen and given the name Ada—after Augusta Ada King, Countess of Lovelace, usually known as Ada Lovelace. This proposal was influenced by the 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. In 1981, Tony Hoare took advantage of his Turing Award speech to criticize Ada for being overly complex and hence unreliable,[20] but subsequently seemed to recant in the foreword he wrote for an Ada textbook.[21]

Ada attracted much attention from the programming community as a whole during its early days. Its backers and others predicted that it might become a dominant language for general purpose programming and not only defense-related work.[22] Ichbiah publicly stated that within ten years, only two programming languages would remain: Ada and Lisp.[23] Early Ada compilers struggled to implement the large, complex language, and both compile-time and run-time performance tended to be slow and tools primitive.[22] Compiler vendors expended most of their efforts in passing the massive, language-conformance-testing, government-required Ada Compiler Validation Capability (ACVC) validation suite that was required in another novel feature of the Ada language effort.[23] The Jargon File, a dictionary of computer hacker slang originating in 1975–1983, notes in an entry on Ada that "it is precisely what one might expect given that kind of endorsement by fiat; designed by committee...difficult to use, and overall a disastrous, multi-billion-dollar boondoggle...Ada Lovelace...would almost certainly blanch at the use her name has been latterly put to; the kindest thing that has been said about it is that there is probably a good small language screaming to get out from inside its vast, elephantine bulk."[24]

The first validated Ada implementation was the NYU Ada/Ed translator,[25] certified on April 11, 1983. NYU Ada/Ed is implemented in the high-level set language SETL.[26] Several commercial companies began offering Ada compilers and associated development tools, including Alsys, TeleSoft, DDC-I, Advanced Computer Techniques, Tartan Laboratories, Irvine Compiler, TLD Systems, and Verdix.[27] Computer manufacturers who had a significant business in the defense, aerospace, or related industries, also offered Ada compilers and tools on their platforms; these included Concurrent Computer Corporation, Cray Research, Inc., Digital Equipment Corporation, Harris Computer Systems, and Siemens Nixdorf Informationssysteme AG.[27]

In 1991, the US Department of Defense began to require the use of Ada (the Ada mandate) for all software,[28] though exceptions to this rule were often granted.[22] The Department of Defense Ada mandate was effectively removed in 1997, as the DoD began to embrace commercial off-the-shelf (COTS) technology.[22] Similar requirements existed in other NATO countries: Ada was required for NATO systems involving command and control and other functions, and Ada was the mandated or preferred language for defense-related applications in countries such as Sweden, Germany, and Canada.[29]

By the late 1980s and early 1990s, Ada compilers had improved in performance, but there were still barriers to fully exploiting Ada's abilities, including a tasking model that was different from what most real-time programmers were used to.[23]

Because of Ada's safety-critical support features, it is now used not only for military applications, but also in commercial projects where a software bug can have severe consequences, e.g., avionics and air traffic control, commercial rockets such as the Ariane 4 and 5, satellites and other space systems, railway transport and banking.[16] For example, the Primary Flight Control System, the fly-by-wire system software in the Boeing 777, was written in Ada, as were the fly-by-wire systems for the aerodynamically unstable Eurofighter Typhoon,[30] Saab Gripen,[31] Lockheed Martin F-22 Raptor and the DFCS replacement flight control system for the Grumman F-14 Tomcat. The Canadian Automated Air Traffic System was written in 1 million lines of Ada (SLOC count). It featured advanced distributed processing, a distributed Ada database, and object-oriented design. Ada is also used in other air traffic systems, e.g., the UK's next-generation Interim Future Area Control Tools Support (iFACTS) air traffic control system is designed and implemented using SPARK Ada.[32] It is also used in the French TVM in-cab signalling system on the TGV high-speed rail system, and the metro suburban trains in Paris, London, Hong Kong and New York City.[16][33]

Standardization edit

Timeline of Ada language
Year Informal name ANSI Standard ISO/IEC Standard
1980 Ada MIL-STD 1815
1983 Ada 83/87 MIL-STD 1815A 8652:1987
1995 Ada 95 8652:1995
2007 Ada 2005 8652:1995/Amd 1:2007
2012 Ada 2012 8652:2012
2023 Ada 2022 8652:2023

Preliminary Ada can be found in ACM Sigplan Notices Vol 14, No 6, June 1979[34]

Ada was first published in 1980 as an ANSI standard ANSI/MIL-STD 1815. As this very first version held many errors and inconsistencies [a], the revised edition was published in 1983 as ANSI/MIL-STD 1815A. Without any further changes, it became an ISO standard in 1987.[36] 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.[37] There is also a French translation; DIN translated it into German as DIN 66268 in 1988.

Ada 95, the joint ISO/IEC/ANSI standard ISO/IEC 8652:1995[38][39] was published in February 1995, making it 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 language. A Technical Corrigendum to Ada 95 was published in October 2001,[40][41] and a major Amendment, ISO/IEC 8652:1995/Amd 1:2007 [42][43] was published on March 9, 2007, commonly known as Ada 2005 because work on the new standard was finished that year.

At the Ada-Europe 2012 conference in Stockholm, the Ada Resource Association (ARA) and Ada-Europe announced the completion of the design of the latest version of the Ada language and the submission of the reference manual to the ISO/IEC JTC 1/SC 22/WG 9 of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) for approval. ISO/IEC 8652:2012[44](see Ada 2012 RM) was published in December 2012, known as Ada 2012. A technical corrigendum, ISO/IEC 8652:2012/COR 1:2016, was published [45](see RM 2012 with TC 1).

On May 2, 2023, the Ada community saw the formal approval of publication of the Ada 2022 edition of the programming language standard.[11]

Despite the names Ada 83, 95 etc., legally there is only one Ada standard, the one of the last ISO/IEC standard: with the acceptance of a new standard version, the previous one becomes withdrawn. The other names are just informal ones referencing a certain edition.

Other related standards include ISO/IEC 8651-3:1988 Information processing systems—Computer graphics—Graphical Kernel System (GKS) language bindings—Part 3: Ada.

Language constructs edit

Ada is an ALGOL-like programming language featuring control structures with reserved words such as if, then, else, while, for, and so on. However, Ada also has many data structuring facilities and other abstractions which were not included in the original ALGOL 60, such as type definitions, records, pointers, enumerations. Such constructs were in part inherited from or inspired by Pascal.

"Hello, world!" in Ada edit

A common example of a language's syntax is the Hello world program: (hello.adb)

with Ada.Text_IO; procedure Hello is begin  Ada.Text_IO.Put_Line ("Hello, world!"); end Hello; 

This program can be compiled by using the freely available open source compiler GNAT, by executing

gnatmake hello.adb 

Data types edit

Ada's type system is not based on a set of predefined primitive types but allows users to declare their own types. This declaration in turn is not based on the internal representation of the type but on describing the goal which should be achieved. This allows the compiler to determine a suitable memory size for the type, and to check for violations of the type definition at compile time and run time (i.e., range violations, buffer overruns, type consistency, etc.). Ada supports numerical types defined by a range, modulo types, aggregate types (records and arrays), and enumeration types. Access types define a reference to an instance of a specified type; untyped pointers are not permitted. Special types provided by the language are task types and protected types.

For example, a date might be represented as:

type Day_type is range 1 .. 31; type Month_type is range 1 .. 12; type Year_type is range 1800 .. 2100; type Hours is mod 24; type Weekday is (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday);  type Date is  record  Day : Day_type;  Month : Month_type;  Year : Year_type;  end record; 

Important to note: Day_type, Month_type, Year_type, Hours are incompatible types, meaning that for instance the following expression is illegal:

Today: Day_type := 4; Current_Month: Month_type := 10; ... Today + Current_Month ... -- illegal 

The predefined plus-operator can only add values of the same type, so the expression is illegal.

Types can be refined by declaring subtypes:

subtype Working_Hours is Hours range 0 .. 12; -- at most 12 Hours to work a day subtype Working_Day is Weekday range Monday .. Friday; -- Days to work  Work_Load: constant array(Working_Day) of Working_Hours -- implicit type declaration  := (Friday => 6, Monday => 4, others => 10); -- lookup table for working hours with initialization 

Types can have modifiers such as limited, abstract, private etc. Private types do not show their inner structure; objects of limited types cannot be copied.[46] Ada 95 adds further features for object-oriented extension of types.

Control structures edit

Ada is a structured programming language, meaning that the flow of control is structured into standard statements. All standard constructs and deep-level early exit are supported, so the use of the also supported "go to" commands is seldom needed.

-- while a is not equal to b, loop. while a /= b loop  Ada.Text_IO.Put_Line ("Waiting"); end loop;  if a > b then  Ada.Text_IO.Put_Line ("Condition met"); else  Ada.Text_IO.Put_Line ("Condition not met"); end if;  for i in 1 .. 10 loop  Ada.Text_IO.Put ("Iteration: ");  Ada.Text_IO.Put (i);  Ada.Text_IO.Put_Line; end loop;  loop  a := a + 1;  exit when a = 10; end loop;  case i is  when 0 => Ada.Text_IO.Put ("zero");  when 1 => Ada.Text_IO.Put ("one");  when 2 => Ada.Text_IO.Put ("two");  -- case statements have to cover all possible cases:  when others => Ada.Text_IO.Put ("none of the above"); end case;  for aWeekday in Weekday'Range loop -- loop over an enumeration  Put_Line ( Weekday'Image(aWeekday) ); -- output string representation of an enumeration  if aWeekday in Working_Day then -- check of a subtype of an enumeration  Put_Line ( " to work for " &  Working_Hours'Image (Work_Load(aWeekday)) ); -- access into a lookup table  end if; end loop; 

Packages, procedures and functions edit

Among the parts of an Ada program are packages, procedures and functions.

Example: Package specification (example.ads)

package Example is  type Number is range 1 .. 11;  procedure Print_and_Increment (j: in out Number); end Example; 

Package body (example.adb)

with Ada.Text_IO; package body Example is   i : Number := Number'First;   procedure Print_and_Increment (j: in out Number) is   function Next (k: in Number) return Number is  begin  return k + 1;  end Next;   begin  Ada.Text_IO.Put_Line ( "The total is: " & Number'Image(j) );  j := Next (j);  end Print_and_Increment;  -- package initialization executed when the package is elaborated begin  while i < Number'Last loop  Print_and_Increment (i);  end loop; end Example; 

This program can be compiled, e.g., by using the freely available open-source compiler GNAT, by executing

gnatmake -z example.adb 

Packages, procedures and functions can nest to any depth, and each can also be the logical outermost block.

Each package, procedure or function can have its own declarations of constants, types, variables, and other procedures, functions and packages, which can be declared in any order.

Pragmas edit

A pragma is a compiler directive that conveys information to the compiler to allow specific manipulating of compiled output.[47] Certain pragmas are built into the language,[48] while others are implementation-specific.

Examples of common usage of compiler pragmas would be to disable certain features, such as run-time type checking or array subscript boundary checking, or to instruct the compiler to insert object code instead of a function call (as C/C++ does with inline functions).

Generics edit

Ada has had generics since it was first designed in 1977–1980. The standard library uses generics to provide many services. Ada 2005 adds a comprehensive generic container library to the standard library, which was inspired by C++'s standard template library.

A generic unit is a package or a subprogram that takes one or more generic formal parameters.

A generic formal parameter is a value, a variable, a constant, a type, a subprogram, or even an instance of another, designated, generic unit. For generic formal types, the syntax distinguishes between discrete, floating-point, fixed-point, access (pointer) types, etc. Some formal parameters can have default values.

To instantiate a generic unit, the programmer passes actual parameters for each formal. The generic instance then behaves just like any other unit. It is possible to instantiate generic units at run-time, for example inside a loop.

See also edit

  • Ada compilers
  • APSE – a specification for a programming environment to support software development in Ada
  • Ravenscar profile – a subset of the Ada tasking features designed for safety-critical hard real-time computing
  • SPARK – a programming language consisting of a highly restricted subset of Ada, annotated with meta-information describing desired component behavior and individual runtime requirements

Notes edit

  1. ^ see Summary of Ada Language Changes[35]
  1. ^ "Ada2012 Rationale" (PDF). adacore.com. (PDF) from the original on 18 April 2016. Retrieved 5 May 2018.
  2. ^ "Commercial software solutions for Ada, C and C++". AdaCore. Retrieved Apr 4, 2023.
  3. ^ "PTC ObjectAda". PTC.com. Retrieved 2014-01-27.
  4. ^ "MapuSoft Ada-C/C++ changer". 16 April 2019.
  5. ^ "Ada 95 Certified Processors List - Details". ada-auth.org. Retrieved Apr 4, 2023.
  6. ^ Ada Rationale, 1986, pp. 23, 70, 110–114, 137, 165, 236
  7. ^ "Chapel spec (Acknowledgements)" (PDF). Cray Inc. 2015-10-01. Archived (PDF) from the original on 2022-10-09. Retrieved 2016-01-14.
  8. ^ . Archived from the original on 2020-09-14. Retrieved 2018-08-06.
  9. ^ "The Griffin Project". cs.nyu.edu. Retrieved Apr 4, 2023.
  10. ^ "SparForte Programming Language". www.sparforte.com. Retrieved Apr 4, 2023.
  11. ^ a b Pinho, Luis Miguel (June 2023). "From the Editor's Desk". Ada Letters. XLIII (1). Association for Computing Machinery: 3. doi:10.1145/3631483 (inactive 31 January 2024).{{cite journal}}: CS1 maint: DOI inactive as of January 2024 (link)
  12. ^ . University of Mich. Archived from the original on 2016-05-22. Retrieved 27 May 2016.
  13. ^ Fuegi, J; Francis, J (2003). "Lovelace & Babbage and the creation of the 1843 'notes'". IEEE Annals of the History of Computing. 25 (4): 16–26. doi:10.1109/MAHC.2003.1253887. S2CID 40077111.
  14. ^ "Concurrency - Chapter 6 - Ada 95 QUALITY AND STYLE Guide". adaic.org. Retrieved November 5, 2021.
  15. ^ Taft, S. Tucker; Olsen, Florence (1999-06-30). . Government Computer News. pp. 2–3. Archived from the original on 2015-08-31. Retrieved 2010-09-14.
  16. ^ a b c Feldman, Michael. "Who's Using Ada? Real-World Projects Powered by the Ada Programming Language November 2014". SIGAda Education Working Group.
  17. ^ no safe dynamic memory management in ADA, in: Writing Linux Kernel Modules in Safe Rust - Geoffrey Thomas & Alex Gaynor , The Linux Foundation, 2019-10-02
  18. ^ "DoD - Strawman Requirements - April 1975". iment.com. Retrieved Apr 4, 2023.
  19. ^ "John Goodenough | SEI Staff Profile". Sei.cmu.edu. Retrieved 2014-01-27.
  20. ^ C.A.R., Hoare (1981). "The Emperor's Old Clothes" (PDF). Communications of the ACM. 24 (2). Association for Computing Machinery: 75–83. doi:10.1145/358549.358561. S2CID 97895. (PDF) from the original on 2016-03-04.
  21. ^ Watt, D.A.; Wichmann, B.A.; Findlay, W. (1987). Ada: Language and Methodology. Prentice-Hall.
  22. ^ a b c d Sward, Ricky E. (November 2010). "The rise, fall and persistence of Ada". SIGAda '10: Proceedings of the ACM SIGAda annual international conference on SIGAda. pp. 71–74. doi:10.1145/1879063.1879081.
  23. ^ a b c Rosen, J-P. (August 2009). "The Ada Paradox(es)". Ada Letters. 24 (2). ACM SIGAda: 28–35. doi:10.1145/1620593.1620597. S2CID 608405.
  24. ^ "THIS IS THE JARGON FILE, VERSION 2.6.2" (TXT). 1991-02-14. Retrieved 2023-01-31.
  25. ^ SofTech Inc. (1983-04-11). . Waltham, MA. Archived from the original on 2012-03-12. Retrieved 2010-12-16.
  26. ^ Dewar, Robert B. K.; Fisher, Gerald A. Jr.; Schonberg, Edmond; Froelich, Robert; Bryant, Stephen; Goss, Clinton F.; Burke, Michael (November 1980). "The NYU Ada translator and interpreter". Proceeding of the ACM-SIGPLAN symposium on Ada programming language - SIGPLAN '80. Vol. 15. pp. 194–201. doi:10.1145/948632.948659. ISBN 0-89791-030-3. S2CID 10586359.
  27. ^ a b "Ada Validated Compilers List". Ada Information Clearinghouse. July 1, 1992. pp. 1–36.
  28. ^ Ada Information Clearinghouse (1983-04-11). . Archived from the original on 2016-03-04. Retrieved 2015-06-07.
  29. ^ Babiak, Nicholas J. (1989). Ada, the New DoD Weapon System Computer Language – Panacea or Calamity (PDF). Air University (United States Air Force). pp. 39–40. (PDF) from the original on December 15, 2019.
  30. ^ "Agile thinking". FlightGlobal. 16 June 1999. from the original on 15 April 2021. Retrieved 13 Feb 2024.
  31. ^ Frisberg, Bo. "Usage of Ada in the Gripen Flight Control System" (PDF). The Special Interest Group on Ada. (PDF) from the original on 15 Jan 2024. Retrieved 13 Feb 2024.
  32. ^ AdaCore. . Archived from the original on 2010-12-24. Retrieved 2011-03-01.
  33. ^ AdaCore. . Archived from the original on 2010-12-24. Retrieved 2011-03-01.
  34. ^ Ichbiah, J. D. (June 1979). "ACM Sigplan Notices". pp. 1–145. doi:10.1145/956650.956651.
  35. ^ Summary of Ada Language Changes
  36. ^ "ISO 8652:1987". ISO. 2013-02-21. Retrieved 2024-01-19.
  37. ^ "Ada 83 LRM, Front Page". archive.adaic.com. Retrieved 2024-01-19.
  38. ^ "ISO/IEC 8652:1995". ISO. Retrieved 2024-01-19.
  39. ^ "Ada 95 Language Reference Manual (original) - Ada Resource Association". www.adaic.org. Retrieved 2024-01-19.
  40. ^ ISO/IEC 8652:1995/Corr 1:2001
  41. ^ Ada 95 RM with TC 1
  42. ^ "ISO/IEC 8652:1995/Amd 1:2007". ISO. Retrieved 2024-01-19.
  43. ^ "Ada Reference Manual, ISO/IEC 8652:2007(E) Ed. 3". www.adaic.org. Retrieved 2024-01-19.
  44. ^ "ISO/IEC 8652:2012". ISO. 2013-03-28. Retrieved 2024-01-19.
  45. ^ "ISO/IEC 8652:2012/Cor 1:2016". ISO. Retrieved 2024-01-19.
  46. ^ (PDF). Archived from the original (PDF) on 6 July 2011. Retrieved 28 February 2011.
  47. ^ "Ada 83 LRM, Sec 2.8: Pragmas". Archive.adaic.com. Retrieved 2014-01-27.
  48. ^ . Archive.adaic.com. Archived from the original on 2012-02-06. Retrieved 2014-01-27.

References edit

International standards edit

Rationale edit

These documents have been published in various forms, including print.

  • Ichbiah, Jean D.; Barnes, John G. P.; Firth, Robert J.; Woodger, Mike (1986), , archived from the original on 2007-02-02 Also available apps.dtic.mil, pdf
  • Barnes, John G. P. (1995), Ada 95 rationale: the language: the standard libraries
  • Barnes, John (2006) [2005], Rationale for Ada 2005

Books edit

  • Booch, Grady (1987). Software Engineering with Ada. California: The Benjamin/Cummings Publishing Company. ISBN 0-8053-0604-8.
  • Skansholm, Jan (1996). Ada 95 From the Beginning. Addison-Wesley. ISBN 0-201-40376-5.
  • Gilpin, Geoff (1985). Ada: A Guided Tour and Tutorial. Prentice hall. ISBN 978-0-13-004045-9.
  • Beidler, John (1997). Data Structures and Algorithms: An Object-Oriented Approach Using Ada 95. Springer-Verlag. ISBN 0-387-94834-1.
  • Gonzalez, Dean W. (1991). Ada Programmer's Handbook. Benjamin-Cummings Publishing Company. ISBN 0-8053-2529-8.
  • Ben-Ari, M. (1998). Ada for Software Engineers. John Wiley & Sons. ISBN 0-471-97912-0.
  • Cohen, Norman (1996). Ada as a Second Language. McGraw-Hill Science/Engineering/Math. ISBN 0-07-011607-5.
  • Burns, Alan; Wellings, Andy (2001). Real-Time Systems and Programming Languages. Ada 95, Real-Time Java and Real-Time POSIX. Addison-Wesley. ISBN 0-201-72988-1.
  • Burns, Alan; Wellings, Andy (1995). Concurrency in Ada. Cambridge University Press. ISBN 0-521-62911-X.
  • Atkinson, Colin (1991). Object-Oriented Reuse, Concurrency and Distribution: An Ada-Based Approach. Addison-Wesley. ISBN 0-201-56527-7.
  • Booch, Grady; Bryan, Doug (1994). Software Engineering with Ada. Addison-Wesley. ISBN 0-8053-0608-0.
  • Jones, Do-While (1989). Ada in Action: With Practical Programming Examples. John Wiley & Sons. ISBN 0-471-60708-8.
  • Stubbs, Daniel; Webre, Neil W. (1993). Data Structures with Abstract Data Types and Ada. Brooks Cole. ISBN 0-534-14448-9.
  • Ledru, Pascal (December 1998). Distributed Programming in Ada with Protected Objects. Dissertation.com. ISBN 1-58112-034-6.
  • Culwin, Fintan (1997). Ada, a Developmental Approach. Prentice Hall. ISBN 0-13-264680-3.
  • English, John; Culwin, Fintan (January 1997). Ada 95 the Craft of Object-Oriented Programming. Prentice Hall. ISBN 0-13-230350-7.
  • Musser, David R.; Stepanov, Alexander (24 October 1989). The Ada Generic Library: Linear List Processing Packages. Springer-Verlag. ISBN 0-387-97133-5.
  • Feldman, Michael B. (1997). Software Construction and Data Structures with Ada 95. Addison-Wesley. ISBN 0-201-88795-9.
  • Johnston, Simon (1997). Ada 95 for C and C++ Programmers. Addison-Wesley. ISBN 0-201-40363-3.
  • Feldman, Michael B.; Koffman, Elliot B. (1992–1993). Ada: Problem Solving and Program Design. Addison-Wesley. ISBN 0-201-52279-9. 795 pages.
  • Feldman, Michael B.; Koffman, Elliot B. (1999). Ada 95. Addison-Wesley. ISBN 0-201-36123-X.
  • Dale, Nell B.; Weems, Chip; McCormick, John (August 1996). Programming and Problem Solving with Ada 95. Jones & Bartlett Publishers. ISBN 0-7637-0293-5.
  • Dale, Nell B.; McCormick, John (2007). Ada Plus Data Structures: An Object-Oriented Approach, 2nd edition. Jones & Bartlett Publishers. ISBN 978-0-7637-3794-8.
  • Krell, Bruce C. (1992). Developing With Ada: Life-Cycle Methods. Bantam Dell Pub Group. ISBN 0-553-09102-6.
  • Bishop, Judy (10 May 1990). Distributed Ada: Developments and Experiences. Cambridge University Press. ISBN 0-521-39251-9.
  • Sanden, Bo (1994). Software Systems Construction With Examples in Ada. Prentice Hall. ISBN 0-13-030834-X.
  • Hillam, Bruce (1994). Introduction to Abstract Data Types Using Ada. Prentice Hall. ISBN 0-13-045949-6.
  • Rudd, David (1994). Introduction to Software Design and Development With Ada. Brooks Cole. ISBN 0-314-02829-3.
  • Pyle, Ian C. (1991). Developing Safety Systems: A Guide Using Ada. Prentice Hall. ISBN 0-13-204298-3.
  • Baker, Louis (1989). Artificial Intelligence With Ada. McGraw-Hill. ISBN 0-07-003350-1.
  • Burns, Alan; Wellings, Andy (1995). HRT-HOOD: A Structured Design Method for Hard Real-Time Ada Systems. North-Holland. ISBN 0-444-82164-3.
  • Savitch, Walter; Peterson, Charles (1992). Ada: An Introduction to the Art and Science of Programming. Benjamin-Cummings Publishing Company. ISBN 0-8053-7070-6.
  • Weiss, Mark Allen (1993). Data Structures and Algorithm Analysis in Ada. Benjamin-Cummings Publishing Company. ISBN 0-8053-9055-3.
  • Ledgard, Henry (1983). Ada: An Introduction (second ed.). Springer-Verlag. ISBN 0-387-90814-5.
  • Bjørner, Dines; Oest, Ole N., eds. (1980). Towards a Formal Description of Ada. London: Springer-Verlag. ISBN 3-540-10283-3.

Further reading edit

External links edit

  • Ada Resource Association
  • DOD Ada programming language (ANSI/MIL STD 1815A-1983) specification
  • JTC1/SC22/WG9 ISO home of Ada Standards
  • Ada (programming language) at Curlie
  • Ada Programming Language Materials, 1981–1990. Charles Babbage Institute, University of Minnesota.


programming, language, structured, statically, typed, imperative, object, oriented, high, level, programming, language, inspired, pascal, other, languages, built, language, support, design, contract, extremely, strong, typing, explicit, concurrency, tasks, syn. Ada is a structured statically typed imperative and object oriented high level programming language inspired by Pascal and other languages It has built in language support for design by contract DbC extremely strong typing explicit concurrency tasks synchronous message passing protected objects and non determinism Ada improves code safety and maintainability by using the compiler to find errors in favor of runtime errors Ada is an international technical standard jointly defined by the International Organization for Standardization ISO and the International Electrotechnical Commission IEC As of May 2023 update the standard called Ada 2022 informally is ISO IEC 8652 2023 11 AdaParadigmMulti paradigm structured imperative object oriented aspect oriented 1 concurrent array distributed generic procedural metaFamilyPascalDesigned byMIL STD 1815 Ada 83 Jean Ichbiah Ada 95 Tucker Taft Ada 2005 Tucker Taft Ada 2012 Tucker TaftFirst appearedFebruary 1980 44 years ago 1980 02 Stable releaseAda 2022 May 2023Typing disciplinestatic strong safe nominalOSMulti or cross platformFilename extensions adb adsWebsiteada lang wbr ioMajor implementationsAdaCore GNAT 2 Green Hills Software Optimising Ada 95 compiler PTC ApexAda and ObjectAda 3 MapuSoft Ada C C changer 4 formerly known as AdaMagic with C Intermediate 5 DDC I ScoreDialectsSPARK Ravenscar profileInfluenced byALGOL 68 Pascal Simula 67 6 C Ada 95 Smalltalk Ada 95 Modula 2 Ada 95 Java Ada 2005 Eiffel Ada 2012 InfluencedC Chapel 7 Drago 8 D Eiffel Griffin 9 Java Nim ParaSail PL SQL PL pgSQL Python Ruby Seed7 SPARforte 10 Sparkel SQL PSM VHDLAda Programming at WikibooksAda was originally designed by a team led by French computer scientist Jean Ichbiah of Honeywell under contract to the United States Department of Defense DoD from 1977 to 1983 to supersede over 450 programming languages used by the DoD at that time 12 Ada was named after Ada Lovelace 1815 1852 who has been credited as the first computer programmer 13 Contents 1 Features 2 History 3 Standardization 4 Language constructs 4 1 Hello world in Ada 4 2 Data types 4 3 Control structures 4 4 Packages procedures and functions 4 5 Pragmas 4 6 Generics 5 See also 6 Notes 7 References 7 1 International standards 7 2 Rationale 7 3 Books 8 Further reading 9 External linksFeatures editAda was originally designed for embedded and real time systems The Ada 95 revision designed by S Tucker Taft of Intermetrics between 1992 and 1995 improved support for systems numerical financial and object oriented programming OOP Features of Ada include strong typing modular programming mechanisms packages run time checking parallel processing tasks synchronous message passing protected objects and nondeterministic select statements exception handling and generics Ada 95 added support for object oriented programming including dynamic dispatch The syntax of Ada minimizes choices of ways to perform basic operations and prefers English keywords such as or else and and then to symbols such as and amp amp Ada uses the basic arithmetical operators and but avoids using other symbols Code blocks are delimited by words such as declare begin and end where the end in most cases is followed by the identifier of the block it closes e g if end if loop end loop In the case of conditional blocks this avoids a dangling else that could pair with the wrong nested if expression in other languages like C or Java Ada is designed for developing very large software systems Ada packages can be compiled separately Ada package specifications the package interface can also be compiled separately without the implementation to check for consistency This makes it possible to detect problems early during the design phase before implementation starts A large number of compile time checks are supported 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 For example the syntax requires explicitly named closing of blocks to prevent errors due to mismatched end tokens The adherence to strong typing allows detecting many common software errors wrong parameters range violations invalid references mismatched types etc either during compile time or otherwise during run time As concurrency is part of the language specification the compiler can in some cases detect potential deadlocks 14 Compilers also commonly check for misspelled identifiers visibility of packages redundant declarations etc and can provide warnings and useful suggestions on how to fix the error Ada also supports run time checks to protect against access to unallocated memory buffer overflow errors range violations off by one errors array access errors and other detectable 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 sometimes used in critical systems where any anomaly might lead to very serious consequences e g accidental death injury or severe financial loss Examples of systems where Ada is used include avionics air traffic control railways banking military and space technology 15 16 Ada s dynamic memory management is high level and type safe Ada has no generic or untyped pointers nor does it implicitly declare any pointer type Instead all dynamic memory allocation and deallocation must occur via explicitly declared access types Each access type has an associated storage pool that handles the low level details of memory management the programmer can either use the default storage pool or define new ones this is particularly relevant for Non Uniform Memory Access It is even possible to declare several different access types that all designate the same type but use different storage pools Also the language provides for accessibility checks both at compile time and at run time that ensures that an access value cannot outlive the type of the object it points to 17 Though the semantics of the language allow automatic garbage collection of inaccessible objects most implementations do not support it by default as it would cause unpredictable behaviour in real time systems Ada does support a limited form of region based memory management also creative use of storage pools can provide for a limited form of automatic garbage collection since destroying a storage pool also destroys all the objects in the pool A double dash resembling an em dash denotes comment text Comments stop at end of line there is intentionally no way to make a comment span multiple lines to prevent unclosed comments from accidentally voiding whole sections of source code Disabling a whole block of code therefore requires the prefixing of each line or column individually with While this clearly denotes disabled code by creating a column of repeated down the page it also renders the experimental dis re enablement of large blocks a more drawn out process in editors without block commenting support The semicolon is a statement terminator and the null or no operation statement is null A single without a statement to terminate is not allowed Unlike most 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 only 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 One notable free software tool that is used by many Ada programmers to aid them in writing Ada source code is the GNAT Programming Studio and GNAT which is part of the GNU Compiler Collection History editIn the 1970s the US Department of Defense DoD became 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 a working group the High Order Language Working Group HOLWG was formed with the intent to reduce this number by finding or creating a programming language generally suitable for the department s and the UK Ministry of Defence s requirements After many iterations beginning with an original straw man proposal 18 the eventual programming language was named Ada The total number of high level programming languages in use for such projects fell from over 450 in 1983 to 37 by 1996 HOLWG crafted the Steelman language requirements a series of documents stating the requirements they felt a programming language should satisfy Many existing languages were formally reviewed but the team concluded in 1977 that no existing language met the specifications nbsp Watercolour painting of Ada LovelaceRequests 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 Honeywell led by Jean Ichbiah Blue SofTech led by John Goodenough 19 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 1979 the Green proposal designed by Jean Ichbiah at Honeywell was chosen and given the name Ada after Augusta Ada King Countess of Lovelace usually known as Ada Lovelace This proposal was influenced by the 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 In 1981 Tony Hoare took advantage of his Turing Award speech to criticize Ada for being overly complex and hence unreliable 20 but subsequently seemed to recant in the foreword he wrote for an Ada textbook 21 Ada attracted much attention from the programming community as a whole during its early days Its backers and others predicted that it might become a dominant language for general purpose programming and not only defense related work 22 Ichbiah publicly stated that within ten years only two programming languages would remain Ada and Lisp 23 Early Ada compilers struggled to implement the large complex language and both compile time and run time performance tended to be slow and tools primitive 22 Compiler vendors expended most of their efforts in passing the massive language conformance testing government required Ada Compiler Validation Capability ACVC validation suite that was required in another novel feature of the Ada language effort 23 The Jargon File a dictionary of computer hacker slang originating in 1975 1983 notes in an entry on Ada that it is precisely what one might expect given that kind of endorsement by fiat designed by committee difficult to use and overall a disastrous multi billion dollar boondoggle Ada Lovelace would almost certainly blanch at the use her name has been latterly put to the kindest thing that has been said about it is that there is probably a good small language screaming to get out from inside its vast elephantine bulk 24 The first validated Ada implementation was the NYU Ada Ed translator 25 certified on April 11 1983 NYU Ada Ed is implemented in the high level set language SETL 26 Several commercial companies began offering Ada compilers and associated development tools including Alsys TeleSoft DDC I Advanced Computer Techniques Tartan Laboratories Irvine Compiler TLD Systems and Verdix 27 Computer manufacturers who had a significant business in the defense aerospace or related industries also offered Ada compilers and tools on their platforms these included Concurrent Computer Corporation Cray Research Inc Digital Equipment Corporation Harris Computer Systems and Siemens Nixdorf Informationssysteme AG 27 In 1991 the US Department of Defense began to require the use of Ada the Ada mandate for all software 28 though exceptions to this rule were often granted 22 The Department of Defense Ada mandate was effectively removed in 1997 as the DoD began to embrace commercial off the shelf COTS technology 22 Similar requirements existed in other NATO countries Ada was required for NATO systems involving command and control and other functions and Ada was the mandated or preferred language for defense related applications in countries such as Sweden Germany and Canada 29 By the late 1980s and early 1990s Ada compilers had improved in performance but there were still barriers to fully exploiting Ada s abilities including a tasking model that was different from what most real time programmers were used to 23 Because of Ada s safety critical support features it is now used not only for military applications but also in commercial projects where a software bug can have severe consequences e g avionics and air traffic control commercial rockets such as the Ariane 4 and 5 satellites and other space systems railway transport and banking 16 For example the Primary Flight Control System the fly by wire system software in the Boeing 777 was written in Ada as were the fly by wire systems for the aerodynamically unstable Eurofighter Typhoon 30 Saab Gripen 31 Lockheed Martin F 22 Raptor and the DFCS replacement flight control system for the Grumman F 14 Tomcat The Canadian Automated Air Traffic System was written in 1 million lines of Ada SLOC count It featured advanced distributed processing a distributed Ada database and object oriented design Ada is also used in other air traffic systems e g the UK s next generation Interim Future Area Control Tools Support iFACTS air traffic control system is designed and implemented using SPARK Ada 32 It is also used in the French TVM in cab signalling system on the TGV high speed rail system and the metro suburban trains in Paris London Hong Kong and New York City 16 33 Standardization editTimeline of Ada language Year Informal name ANSI Standard ISO IEC Standard1980 Ada MIL STD 1815 1983 Ada 83 87 MIL STD 1815A 8652 19871995 Ada 95 8652 19952007 Ada 2005 8652 1995 Amd 1 20072012 Ada 2012 8652 20122023 Ada 2022 8652 2023Preliminary Ada can be found in ACM Sigplan Notices Vol 14 No 6 June 1979 34 Ada was first published in 1980 as an ANSI standard ANSI MIL STD 1815 As this very first version held many errors and inconsistencies a the revised edition was published in 1983 as ANSI MIL STD 1815A Without any further changes it became an ISO standard in 1987 36 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 37 There is also a French translation DIN translated it into German as DIN 66268 in 1988 Ada 95 the joint ISO IEC ANSI standard ISO IEC 8652 1995 38 39 was published in February 1995 making it 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 language A Technical Corrigendum to Ada 95 was published in October 2001 40 41 and a major Amendment ISO IEC 8652 1995 Amd 1 2007 42 43 was published on March 9 2007 commonly known as Ada 2005 because work on the new standard was finished that year At the Ada Europe 2012 conference in Stockholm the Ada Resource Association ARA and Ada Europe announced the completion of the design of the latest version of the Ada language and the submission of the reference manual to the ISO IEC JTC 1 SC 22 WG 9 of the International Organization for Standardization ISO and the International Electrotechnical Commission IEC for approval ISO IEC 8652 2012 44 see Ada 2012 RM was published in December 2012 known as Ada 2012 A technical corrigendum ISO IEC 8652 2012 COR 1 2016 was published 45 see RM 2012 with TC 1 On May 2 2023 the Ada community saw the formal approval of publication of the Ada 2022 edition of the programming language standard 11 Despite the names Ada 83 95 etc legally there is only one Ada standard the one of the last ISO IEC standard with the acceptance of a new standard version the previous one becomes withdrawn The other names are just informal ones referencing a certain edition Other related standards include ISO IEC 8651 3 1988 Information processing systems Computer graphics Graphical Kernel System GKS language bindings Part 3 Ada Language constructs editAda is an ALGOL like programming language featuring control structures with reserved words such as if then else while for and so on However Ada also has many data structuring facilities and other abstractions which were not included in the original ALGOL 60 such as type definitions records pointers enumerations Such constructs were in part inherited from or inspired by Pascal Hello world in Ada edit A common example of a language s syntax is the Hello world program hello adb with Ada Text IO procedure Hello is begin Ada Text IO Put Line Hello world end Hello This program can be compiled by using the freely available open source compiler GNAT by executing gnatmake hello adb Data types edit Ada s type system is not based on a set of predefined primitive types but allows users to declare their own types This declaration in turn is not based on the internal representation of the type but on describing the goal which should be achieved This allows the compiler to determine a suitable memory size for the type and to check for violations of the type definition at compile time and run time i e range violations buffer overruns type consistency etc Ada supports numerical types defined by a range modulo types aggregate types records and arrays and enumeration types Access types define a reference to an instance of a specified type untyped pointers are not permitted Special types provided by the language are task types and protected types For example a date might be represented as type Day type is range 1 31 type Month type is range 1 12 type Year type is range 1800 2100 type Hours is mod 24 type Weekday is Monday Tuesday Wednesday Thursday Friday Saturday Sunday type Date is record Day Day type Month Month type Year Year type end record Important to note Day type Month type Year type Hours are incompatible types meaning that for instance the following expression is illegal Today Day type 4 Current Month Month type 10 Today Current Month illegal The predefined plus operator can only add values of the same type so the expression is illegal Types can be refined by declaring subtypes subtype Working Hours is Hours range 0 12 at most 12 Hours to work a day subtype Working Day is Weekday range Monday Friday Days to work Work Load constant array Working Day of Working Hours implicit type declaration Friday gt 6 Monday gt 4 others gt 10 lookup table for working hours with initialization Types can have modifiers such as limited abstract private etc Private types do not show their inner structure objects of limited types cannot be copied 46 Ada 95 adds further features for object oriented extension of types Control structures edit Ada is a structured programming language meaning that the flow of control is structured into standard statements All standard constructs and deep level early exit are supported so the use of the also supported go to commands is seldom needed while a is not equal to b loop while a b loop Ada Text IO Put Line Waiting end loop if a gt b then Ada Text IO Put Line Condition met else Ada Text IO Put Line Condition not met end if for i in 1 10 loop Ada Text IO Put Iteration Ada Text IO Put i Ada Text IO Put Line end loop loop a a 1 exit when a 10 end loop case i is when 0 gt Ada Text IO Put zero when 1 gt Ada Text IO Put one when 2 gt Ada Text IO Put two case statements have to cover all possible cases when others gt Ada Text IO Put none of the above end case for aWeekday in Weekday Range loop loop over an enumeration Put Line Weekday Image aWeekday output string representation of an enumeration if aWeekday in Working Day then check of a subtype of an enumeration Put Line to work for amp Working Hours Image Work Load aWeekday access into a lookup table end if end loop Packages procedures and functions edit Among the parts of an Ada program are packages procedures and functions Example Package specification example ads package Example is type Number is range 1 11 procedure Print and Increment j in out Number end Example Package body example adb with Ada Text IO package body Example is i Number Number First procedure Print and Increment j in out Number is function Next k in Number return Number is begin return k 1 end Next begin Ada Text IO Put Line The total is amp Number Image j j Next j end Print and Increment package initialization executed when the package is elaborated begin while i lt Number Last loop Print and Increment i end loop end Example This program can be compiled e g by using the freely available open source compiler GNAT by executing gnatmake z example adb Packages procedures and functions can nest to any depth and each can also be the logical outermost block Each package procedure or function can have its own declarations of constants types variables and other procedures functions and packages which can be declared in any order Pragmas edit A pragma is a compiler directive that conveys information to the compiler to allow specific manipulating of compiled output 47 Certain pragmas are built into the language 48 while others are implementation specific Examples of common usage of compiler pragmas would be to disable certain features such as run time type checking or array subscript boundary checking or to instruct the compiler to insert object code instead of a function call as C C does with inline functions Generics edit This section is an excerpt from Generic programming Generics in Ada edit Ada has had generics since it was first designed in 1977 1980 The standard library uses generics to provide many services Ada 2005 adds a comprehensive generic container library to the standard library which was inspired by C s standard template library A generic unit is a package or a subprogram that takes one or more generic formal parameters A generic formal parameter is a value a variable a constant a type a subprogram or even an instance of another designated generic unit For generic formal types the syntax distinguishes between discrete floating point fixed point access pointer types etc Some formal parameters can have default values To instantiate a generic unit the programmer passes actual parameters for each formal The generic instance then behaves just like any other unit It is possible to instantiate generic units at run time for example inside a loop See also edit nbsp Computer programming portalAda compilers APSE a specification for a programming environment to support software development in Ada Ravenscar profile a subset of the Ada tasking features designed for safety critical hard real time computing SPARK a programming language consisting of a highly restricted subset of Ada annotated with meta information describing desired component behavior and individual runtime requirementsNotes edit see Summary of Ada Language Changes 35 Ada2012 Rationale PDF adacore com Archived PDF from the original on 18 April 2016 Retrieved 5 May 2018 Commercial software solutions for Ada C and C AdaCore Retrieved Apr 4 2023 PTC ObjectAda PTC com Retrieved 2014 01 27 MapuSoft Ada C C changer 16 April 2019 Ada 95 Certified Processors List Details ada auth org Retrieved Apr 4 2023 Ada Rationale 1986 pp 23 70 110 114 137 165 236 Chapel spec Acknowledgements PDF Cray Inc 2015 10 01 Archived PDF from the original on 2022 10 09 Retrieved 2016 01 14 Drago Archived from the original on 2020 09 14 Retrieved 2018 08 06 The Griffin Project cs nyu edu Retrieved Apr 4 2023 SparForte Programming Language www sparforte com Retrieved Apr 4 2023 a b Pinho Luis Miguel June 2023 From the Editor s Desk Ada Letters XLIII 1 Association for Computing Machinery 3 doi 10 1145 3631483 inactive 31 January 2024 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint DOI inactive as of January 2024 link The Ada Programming Language University of Mich Archived from the original on 2016 05 22 Retrieved 27 May 2016 Fuegi J Francis J 2003 Lovelace amp Babbage and the creation of the 1843 notes IEEE Annals of the History of Computing 25 4 16 26 doi 10 1109 MAHC 2003 1253887 S2CID 40077111 Concurrency Chapter 6 Ada 95 QUALITY AND STYLE Guide adaic org Retrieved November 5 2021 Taft S Tucker Olsen Florence 1999 06 30 Ada helps churn out less buggy code Government Computer News pp 2 3 Archived from the original on 2015 08 31 Retrieved 2010 09 14 a b c Feldman Michael Who s Using Ada Real World Projects Powered by the Ada Programming Language November 2014 SIGAda Education Working Group no safe dynamic memory management in ADA in Writing Linux Kernel Modules in Safe Rust Geoffrey Thomas amp Alex Gaynor The Linux Foundation 2019 10 02 DoD Strawman Requirements April 1975 iment com Retrieved Apr 4 2023 John Goodenough SEI Staff Profile Sei cmu edu Retrieved 2014 01 27 C A R Hoare 1981 The Emperor s Old Clothes PDF Communications of the ACM 24 2 Association for Computing Machinery 75 83 doi 10 1145 358549 358561 S2CID 97895 Archived PDF from the original on 2016 03 04 Watt D A Wichmann B A Findlay W 1987 Ada Language and Methodology Prentice Hall a b c d Sward Ricky E November 2010 The rise fall and persistence of Ada SIGAda 10 Proceedings of the ACM SIGAda annual international conference on SIGAda pp 71 74 doi 10 1145 1879063 1879081 a b c Rosen J P August 2009 The Ada Paradox es Ada Letters 24 2 ACM SIGAda 28 35 doi 10 1145 1620593 1620597 S2CID 608405 THIS IS THE JARGON FILE VERSION 2 6 2 TXT 1991 02 14 Retrieved 2023 01 31 SofTech Inc 1983 04 11 Ada Compiler Validation Summary Report NYU Ada ED Version 19 7 V 001 Waltham MA Archived from the original on 2012 03 12 Retrieved 2010 12 16 Dewar Robert B K Fisher Gerald A Jr Schonberg Edmond Froelich Robert Bryant Stephen Goss Clinton F Burke Michael November 1980 The NYU Ada translator and interpreter Proceeding of the ACM SIGPLAN symposium on Ada programming language SIGPLAN 80 Vol 15 pp 194 201 doi 10 1145 948632 948659 ISBN 0 89791 030 3 S2CID 10586359 a b Ada Validated Compilers List Ada Information Clearinghouse July 1 1992 pp 1 36 Ada Information Clearinghouse 1983 04 11 The Congressional Ada Mandate Archived from the original on 2016 03 04 Retrieved 2015 06 07 Babiak Nicholas J 1989 Ada the New DoD Weapon System Computer Language Panacea or Calamity PDF Air University United States Air Force pp 39 40 Archived PDF from the original on December 15 2019 Agile thinking FlightGlobal 16 June 1999 Archived from the original on 15 April 2021 Retrieved 13 Feb 2024 Frisberg Bo Usage of Ada in the Gripen Flight Control System PDF The Special Interest Group on Ada Archived PDF from the original on 15 Jan 2024 Retrieved 13 Feb 2024 AdaCore GNAT Pro Chosen for UK s Next Generation ATC System Archived from the original on 2010 12 24 Retrieved 2011 03 01 AdaCore Look Who s Using Ada Archived from the original on 2010 12 24 Retrieved 2011 03 01 Ichbiah J D June 1979 ACM Sigplan Notices pp 1 145 doi 10 1145 956650 956651 Summary of Ada Language Changes ISO 8652 1987 ISO 2013 02 21 Retrieved 2024 01 19 Ada 83 LRM Front Page archive adaic com Retrieved 2024 01 19 ISO IEC 8652 1995 ISO Retrieved 2024 01 19 Ada 95 Language Reference Manual original Ada Resource Association www adaic org Retrieved 2024 01 19 ISO IEC 8652 1995 Corr 1 2001 Ada 95 RM with TC 1 ISO IEC 8652 1995 Amd 1 2007 ISO Retrieved 2024 01 19 Ada Reference Manual ISO IEC 8652 2007 E Ed 3 www adaic org Retrieved 2024 01 19 ISO IEC 8652 2012 ISO 2013 03 28 Retrieved 2024 01 19 ISO IEC 8652 2012 Cor 1 2016 ISO Retrieved 2024 01 19 Ada Syntax Card PDF Archived from the original PDF on 6 July 2011 Retrieved 28 February 2011 Ada 83 LRM Sec 2 8 Pragmas Archive adaic com Retrieved 2014 01 27 Ada 83 LRM Appendix Annex B Predefined Language Pragmas Archive adaic com Archived from the original on 2012 02 06 Retrieved 2014 01 27 References editInternational standards edit ISO IEC 8652 Information technology Programming languages Ada ISO IEC 15291 Information technology Programming languages Ada Semantic Interface Specification ASIS ISO IEC 18009 Information technology Programming languages Ada Conformity assessment of a language processor ACATS IEEE Standard 1003 5b 1996 the POSIX Ada binding Ada Language Mapping Specification the CORBA interface description language IDL to Ada mappingRationale edit These documents have been published in various forms including print Ichbiah Jean D Barnes John G P Firth Robert J Woodger Mike 1986 Rationale for the Design of the Ada Programming Language archived from the original on 2007 02 02 Also available apps dtic mil pdf Barnes John G P 1995 Ada 95 rationale the language the standard libraries Barnes John 2006 2005 Rationale for Ada 2005Books edit Booch Grady 1987 Software Engineering with Ada California The Benjamin Cummings Publishing Company ISBN 0 8053 0604 8 Skansholm Jan 1996 Ada 95 From the Beginning Addison Wesley ISBN 0 201 40376 5 Gilpin Geoff 1985 Ada A Guided Tour and Tutorial Prentice hall ISBN 978 0 13 004045 9 Beidler John 1997 Data Structures and Algorithms An Object Oriented Approach Using Ada 95 Springer Verlag ISBN 0 387 94834 1 Gonzalez Dean W 1991 Ada Programmer s Handbook Benjamin Cummings Publishing Company ISBN 0 8053 2529 8 Ben Ari M 1998 Ada for Software Engineers John Wiley amp Sons ISBN 0 471 97912 0 Cohen Norman 1996 Ada as a Second Language McGraw Hill Science Engineering Math ISBN 0 07 011607 5 Burns Alan Wellings Andy 2001 Real Time Systems and Programming Languages Ada 95 Real Time Java and Real Time POSIX Addison Wesley ISBN 0 201 72988 1 Burns Alan Wellings Andy 1995 Concurrency in Ada Cambridge University Press ISBN 0 521 62911 X Atkinson Colin 1991 Object Oriented Reuse Concurrency and Distribution An Ada Based Approach Addison Wesley ISBN 0 201 56527 7 Booch Grady Bryan Doug 1994 Software Engineering with Ada Addison Wesley ISBN 0 8053 0608 0 Jones Do While 1989 Ada in Action With Practical Programming Examples John Wiley amp Sons ISBN 0 471 60708 8 Stubbs Daniel Webre Neil W 1993 Data Structures with Abstract Data Types and Ada Brooks Cole ISBN 0 534 14448 9 Ledru Pascal December 1998 Distributed Programming in Ada with Protected Objects Dissertation com ISBN 1 58112 034 6 Culwin Fintan 1997 Ada a Developmental Approach Prentice Hall ISBN 0 13 264680 3 English John Culwin Fintan January 1997 Ada 95 the Craft of Object Oriented Programming Prentice Hall ISBN 0 13 230350 7 Musser David R Stepanov Alexander 24 October 1989 The Ada Generic Library Linear List Processing Packages Springer Verlag ISBN 0 387 97133 5 Feldman Michael B 1997 Software Construction and Data Structures with Ada 95 Addison Wesley ISBN 0 201 88795 9 Johnston Simon 1997 Ada 95 for C and C Programmers Addison Wesley ISBN 0 201 40363 3 Feldman Michael B Koffman Elliot B 1992 1993 Ada Problem Solving and Program Design Addison Wesley ISBN 0 201 52279 9 795 pages Feldman Michael B Koffman Elliot B 1999 Ada 95 Addison Wesley ISBN 0 201 36123 X Dale Nell B Weems Chip McCormick John August 1996 Programming and Problem Solving with Ada 95 Jones amp Bartlett Publishers ISBN 0 7637 0293 5 Dale Nell B McCormick John 2007 Ada Plus Data Structures An Object Oriented Approach 2nd edition Jones amp Bartlett Publishers ISBN 978 0 7637 3794 8 Krell Bruce C 1992 Developing With Ada Life Cycle Methods Bantam Dell Pub Group ISBN 0 553 09102 6 Bishop Judy 10 May 1990 Distributed Ada Developments and Experiences Cambridge University Press ISBN 0 521 39251 9 Sanden Bo 1994 Software Systems Construction With Examples in Ada Prentice Hall ISBN 0 13 030834 X Hillam Bruce 1994 Introduction to Abstract Data Types Using Ada Prentice Hall ISBN 0 13 045949 6 Rudd David 1994 Introduction to Software Design and Development With Ada Brooks Cole ISBN 0 314 02829 3 Pyle Ian C 1991 Developing Safety Systems A Guide Using Ada Prentice Hall ISBN 0 13 204298 3 Baker Louis 1989 Artificial Intelligence With Ada McGraw Hill ISBN 0 07 003350 1 Burns Alan Wellings Andy 1995 HRT HOOD A Structured Design Method for Hard Real Time Ada Systems North Holland ISBN 0 444 82164 3 Savitch Walter Peterson Charles 1992 Ada An Introduction to the Art and Science of Programming Benjamin Cummings Publishing Company ISBN 0 8053 7070 6 Weiss Mark Allen 1993 Data Structures and Algorithm Analysis in Ada Benjamin Cummings Publishing Company ISBN 0 8053 9055 3 Ledgard Henry 1983 Ada An Introduction second ed Springer Verlag ISBN 0 387 90814 5 Bjorner Dines Oest Ole N eds 1980 Towards a Formal Description of Ada London Springer Verlag ISBN 3 540 10283 3 Further reading editBarnes John 2006 Programming in Ada 2005 Addison Wesley ISBN 0 321 34078 7 Barnes John 1991 Programming in Ada plus Language Reference Manual Addison Wesley ISBN 0 201 56539 0 Barnes John 1998 Programming in Ada 95 Addison Wesley ISBN 0 201 34293 6 Barnes John 1997 High Integrity Ada The SPARK Approach Addison Wesley ISBN 0 201 17517 7 Barnes John 2003 High Integrity Software The SPARK Approach to Safety and Security Addison Wesley ISBN 0 321 13616 0 External links edit nbsp Wikimedia Commons has media related to Ada programming language nbsp Wikibooks has a book on the topic of Ada Programming nbsp Wikisource has several original texts related to Ada nbsp Wikiversity has learning resources about Ada Ada Resource Association DOD Ada programming language ANSI MIL STD 1815A 1983 specification JTC1 SC22 WG9 ISO home of Ada Standards Ada programming language at Curlie Ada Programming Language Materials 1981 1990 Charles Babbage Institute University of Minnesota Retrieved from https en wikipedia org w index php title Ada programming language amp oldid 1216154344, wikipedia, wiki, book, books, library,

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