Pascal (programming language): Difference between revisions

Revision as of 11:05, 20 March 2024

Revision as of 00:54, 27 March 2024

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==History==

===Earlier efforts===

Much of the history of [[computer language]] design during the 1960s can be traced to the [[ALGOL 60]] language. ALGOL was developed during the 1950s with the explicit goal of being able to clearly describe algorithms[[algorithm]]s. It included a number of features for [[structured programming]] that remain common in languages to this day.

Shortly after its introduction, in 1962 Wirth began working on his dissertation with Helmut Weber on the [[Euler (programming language)|Euler programming language]]. Euler was based on ALGOL's syntax and many concepts but was not a derivative. Its primary goal was to add dynamic lists and types, allowing it to be used in roles similar to [[Lisp (programming language)|Lisp]]. The language was published in 1965.

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A generation of students used Pascal as an introductory language in undergraduate courses.

One of the early successes for the language was the introduction of [[UCSD Pascal]], a version that ran on a custom [[operating system]] that could be ported to different platforms. A key platform was the [[Apple II series|Apple II]], where it saw widespread use as [[Apple Pascal]]. This led to Pascal becoming the primary [[high-level language]] used for development in the [[Apple Lisa]], and later, the [[Mac (computer)|Macintosh]]. Parts of the original [[Classic Mac OS|Macintosh operating system]] were hand-translated into [[Motorola 68000]] [[assembly language]] from the Pascal [[source code]].<ref>Hertzfeld, Andy. "[http://www.folklore.org/StoryView.py?project=Macintosh&story=Hungarian.txt&topic=Software%20Design&sortOrder=Sort%20by%20Date&detail=medium Hungarian folklore.org] {{webarchive|url=https://web.archive.org/web/20151118082558/http://www.folklore.org/StoryView.py?project=Macintosh&story=Hungarian.txt&topic=Software%20Design&sortOrder=Sort%20by%20Date&detail=medium |date=2015-11-18}}: Macintosh Stories. Retrieved 2012-03-06.</ref>

The [[typesetting]] system [[TeX]] by [[Donald Knuth]] was written in [[WEB]], the original [[literate programming]] system, based on [[Digital Equipment Corporation|DEC]] [[PDP-10]] Pascal. Successful commercial applications like [[Adobe Photoshop]]<ref>https://www.computerhistory.org/atchm/adobe-photoshop-source-code/ {{Webarchive|url=https://web.archive.org/web/20140507131754/http://www.computerhistory.org/atchm/adobe-photoshop-source-code/ |date=2014-05-07}}, Adobe Photoshop Source Code</ref> were written in [[Macintosh Programmer's Workshop]] Pascal, while applications like [[Total Commander]], [[Skype]]<ref>{{cite web |url=https://www.embarcadero.com/products/rad-studio/application-showcase|title=RAD Studio Application Showcase|date=2021-10-29}}</ref> and [[Macromedia Captivate]] were written in Delphi ([[Object Pascal]]). [[Apollo Computer]] used Pascal as the systems programming language for its operating systems beginning in 1980.

Variants of Pascal have also been used for everything from research projects to [[PC game]]s and [[embedded system]]s. Newer Pascal compilers exist which are widely used.<ref>[http://www.tiobe.com/index.php/content/paperinfo/tpci/ tiobe.com] {{webarchive|url=https://web.archive.org/web/20120315012717/http://www.tiobe.com/index.php/content/paperinfo/tpci |date=2012-03-15}}, Programming Community Index for January 2011.</ref>

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During work on the Lisa, [[Larry Tesler]] began corresponding with Wirth on the idea of adding object-oriented extensions to the language, to make Pascal a [[Programming paradigm|Multi-paradigm programming language]]. This led initially to [[Clascal]], introduced in 1983. As the Lisa program faded and was replaced by the Macintosh, a further version was created and named [[Object Pascal]]. This was introduced on the Mac in 1985 as part of the [[MacApp]] [[application framework]], and became Apple's main development language into the early 1990s.

The Object Pascal extensions were added to [[Turbo Pascal]] with the release of version 5.5 in 1989.<ref>{{cite web|title=Antique Software: Turbo Pascal v5.5|url=http://edn.embarcadero.com/article/20803|access-date=2018-05-17|archive-date=2010-11-24|archive-url=https://web.archive.org/web/20101124090934/http://edn.embarcadero.com/article/20803|url-status=dead}}</ref> Over the years, Object Pascal became the basis of the [[Delphi (software)|Delphi]] system for [[Microsoft Windows]], which is still used for developing Windows applications, and can [[cross-compile]] code to other systems. [[Free Pascal]] is an open source, cross-platform alternative with its own graphical [[integrated development environment|IDE]] called [[Lazarus (IDE)|Lazarus]].

==Implementations==

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==={{anchor|Pascal-P}}The Pascal-P system===

To propagate the language rapidly, a compiler ''porting kit'' was created in Zürich that included a compiler that generated so called [[p-code machine|p-code]] for a ''virtual'' stack machine, i.e., code that lends itself to reasonably efficient interpretation, along with an interpreter for that code – the ''Pascal-P'' system. The P-system compilers were named Pascal-P1, Pascal-P2, Pascal-P3, and Pascal-P4. Pascal-P1 was the first version, and Pascal-P4 was the last to come from Zürich. The version termed Pascal-P1 was coined after the fact for the many different sources for Pascal-P that existed. The compiler was redesigned to enhance [[software portability|portability]], and issued as Pascal-P2. This code was later enhanced to become Pascal-P3, with an intermediate code [[backward compatible]] with Pascal-P2, and Pascal-P4, which was not backward compatible.

The Pascal-P4 compiler–interpreter can still be run and compiled on systems compatible with original Pascal (as can Pascal-P2). However, it only accepts a subset of the Pascal language.

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The universities of [[University of Wisconsin–Madison|Wisconsin–Madison]], [[University of Zurich|Zürich]], [[Karlsruhe Institute of Technology|Karlsruhe]], and [[University of Wuppertal|Wuppertal]] developed the ''Pascal-SC''<ref>{{cite journal |last1=Rall |first1=L. B. |date=1987 |title=An introduction to the scientific computing language Pascal-SC |journal=Computers |volume=14 |pages=53–69 |doi=10.1016/0898-1221(87)90181-7|doi-access=}}</ref><ref name="Cadmus_1986">{{cite journal |title=Cadmus jetzt mit Kulisch-Arithmetik - Uni Karlsruhe gibt Pascal-Compiler nach München |trans-title=Cadmus now comes with Kulisch arithmetic - University Karlsruhe delivers Pascal compiler to Munich |author=PI |date=1986-08-29 |journal=[[Computerwoche]] |publisher=[[IDG Business Media GmbH]] |language=de |___location=Munich – Karlsruhe, Germany |url=http://www.computerwoche.de/a/uni-karlsruhe-gibt-pascal-compiler-nach-muenchen-cadmus-jetzt-mit-kulisch-arithmetik,1165749 |access-date=2016-05-30 |url-status=dead |archive-url=https://web.archive.org/web/20160530220339/http://www.computerwoche.de/a/uni-karlsruhe-gibt-pascal-compiler-nach-muenchen-cadmus-jetzt-mit-kulisch-arithmetik,1165749 |archive-date=2016-05-30}}</ref> and ''Pascal-XSC''<ref>{{cite web |url=http://www.rz.uni-karlsruhe.de/~iam/html/language/pxsc.html |title=Pascal-XSC: Pascal for Extended Scientific Computing |url-status=dead |archive-url=https://web.archive.org/web/20140105102206/http://www.rz.uni-karlsruhe.de/~iam/html/language/pxsc.html |archive-date=2014-01-05}}</ref><ref>{{cite web |url=http://www.xsc.de/ |title=XSC Software |access-date=11 August 2015 |url-status=dead |archive-url=https://web.archive.org/web/20151101160306/http://www.xsc.de/ |archive-date=1 November 2015}}</ref><ref>{{cite web |url=http://www2.math.uni-wuppertal.de/wrswt/xsc/pxsc_download.html |title=Universitaet Wuppertal: Wissenschaftliches Rechnen / Softwaretechnologie |access-date=11 August 2015 |url-status=dead |archive-url=https://web.archive.org/web/20151106022857/http://www2.math.uni-wuppertal.de/wrswt/xsc/pxsc_download.html |archive-date=6 November 2015}}</ref> (''[[Extensions for Scientific Computation]]'') compilers, aimed at programming numerical computations. Development for Pascal-SC started in 1978 supporting ISO 7185 Pascal level 0, but level 2 support was added at a later stage.<ref name="Wallis_1990">{{cite book |title=Improving Floating-Point Programming |editor-first=Peter J. L. |editor-last=Wallis |author-first1=Lothar |author-last1=Bamberger |author-first2=James H. |author-last2=Davenport |author-first3=Hans-Christoph |author-last3=Fischer |author-first4=Jan |author-last4=Kok |author-first5=Günter |author-last5=Schumacher |author-first6=Christian |author-last6=Ullrich |author-first7=Peter J. L. |author-last7=Wallis |author-first8=Dik T. |author-last8=Winter |author-first9=Jürgen |author-last9=Wolff von Gudenberg |date=1990 |edition=1st |publisher=[[John Wiley & Sons Ltd.]] |___location=Bath, United Kingdom |isbn=0-471-92437-7 <!--|ISBN=978-0-471-92437-1 -->}}</ref> Pascal-SC originally targeted the [[Z80]] processor, but was later rewritten for DOS ([[x86]]) and [[Motorola 68000|68000]]. Pascal-XSC has at various times been ported to Unix (Linux, [[SunOS]], [[HP-UX]], [[IBM AIX|AIX]]) and Microsoft/IBM (DOS with [[EMX (programming environment)|EMX]], OS/2, [[Windows]]) operating systems. It operates by generating intermediate C source code which is then compiled to a native executable. Some of the Pascal-SC language extensions have been adopted by [[GNU Pascal]].

Pascal Sol was designed around 1983 by a French team to implement a [[Unix-like]] system named Sol. It was standard Pascal level-1 (with parameterized array bounds) but the definition allowed alternative keywords and predefined identifiers in French and the language included a few extensions to ease system programming (e.g. an equivalent to lseek).<ref>Michel Gien, "The SOL Operating System", in Usenix Summer '83 Conference, Toronto, ON, (July 1983), pp. 75–78</ref> The Sol team later on moved to the [[ChorusOS]] project to design a [[distributed operating system]].<ref>{{Cite web|url=http://www.cs.berkeley.edu/~prabal/resources/osprelim/RAA+92.pdf|archiveurl=https://web.archive.org/web/20150207194433/http://www.cs.berkeley.edu/~prabal/resources/osprelim/RAA+92.pdf|url-status=dead|title=Overview of the CHORUS Distributed Operating Systems|year=1991|work=Chorus systems|via=cs.berkeley.edu|archivedate=February 7, 2015}}</ref>

[[IP Pascal]] is an implementation of the Pascal programming language using [[Micropolis (company)|Micropolis]] DOS, but was moved rapidly to [[CP/M-80]] running on the Z80. It was moved to the [[80386]] machine types in 1994, and exists today as [[Windows/ XP]] and Linux implementations. In 2008, the system was brought up to a new level and the resulting language termed "Pascaline" (after [[Pascal's calculator]]). It includes objects, [[namespace]] controls, [[dynamic array]]s, and many other extensions, and generally features the same functionality and type protection as [[C Sharp (programming language)|C#]]. It is the only such implementation that is also compatible with the original Pascal implementation, which is standardized as ISO 7185.

==Language constructs==

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* [[Pascal-P4]] compiler, the basis for many subsequent Pascal-implemented-in-Pascal compilers. It implements a subset of full Pascal.

* [[Pascal-P5]] compiler is an ISO 7185 (full Pascal) adaption of Pascal-P4.

* [[Pascal-P6]] compiler is an extended version of Pascal adaption of Pascal-P5 according to the Pascaline language specification.

* Smart Mobile Studio is a Pascal to [[HTML5]]/[[Javascript]] compiler

* [[Turbo Pascal]] was the dominant Pascal compiler for PCs during the 1980s and early 1990s, popular both because of its powerful extensions and extremely short compilation times. Turbo Pascal was compactly written and could compile, run, and debug all from memory without accessing disk. Slow [[floppy disk drivesdrive]]s were common for programmers at the time, further magnifying Turbo Pascal's speed advantage. Currently, older versions of Turbo Pascal (up to 5.5) are available for free download from Borland's site.

* [[IP Pascal]] implements the language "Pascaline" (named after [[Pascal's calculator]]), which is a highly extended Pascal compatible with original Pascal according to ISO 7185. It features modules with namespace control, including parallel tasking modules with semaphores, objects, dynamic arrays of any dimensions that are allocated at runtime, overloads, overrides, and many other extensions. IP Pascal has a built-in portability library that is custom tailored to the Pascal language. For example, a standard text output application from 1970's original Pascal can be recompiled to work in a window and even have graphical constructs added.

* Pascal-XT was created by [[Siemens]] for their [[mainframe computer|mainframe]] operating systems [[BS2000]] and [[SINIX]].

* PocketStudio is a Pascal subset compiler and RAD tool for [[Palm OS]] and MC68xxx processors with some of its own extensions to assist interfacing with the Palm OS [[application programming interface|API]]. It resembles Delphi and Lazarus with a visual form designer, an object inspector and a [[source code editor]].

* MIDletPascal – A Pascal compiler and IDE that generates small and fast Java bytecode specifically designed to create software for mobiles.

* Vector Pascal is a language for [[SIMD]] instruction sets such as the [[MMX (instruction set)|MMX]] and the [[AMD]] [[3DNow!|3d Now]], supporting all [[Intel]] and AMD processors, and [[Sony]]'s [[PlayStation 2]] [[Emotion Engine]].

* Morfik Pascal allows the development of [[Web applicationsapplication]]s entirely written in Object Pascal (both server and browser side).

* WDSibyl – Visual Development Environment and Pascal compiler for Win32 and OS/2.

* PP Compiler, a compiler for Palm OS that runs directly on the handheld computer.

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* [[Dev-Pascal]] is a Pascal [[integrated development environment|IDE]] that was designed in Borland [[Object Pascal|Delphi]] and which supports Free Pascal and GNU Pascal as backends.

* [[Lazarus (software)|Lazarus]] is a free Delphi-like visual cross-platform IDE for [[rapid application development]] (RAD). Based on [[Free Pascal]], Lazarus is available for numerous platforms including [[Linux]], [[FreeBSD]], [[macOS]] and [[Microsoft Windows]].

* Fire (macOS) and Water (Windows) for the [[Oxygene (programming language)|Oxygene]] and the [[Elements Compiler]]

===Libraries===

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Software products ([[compiler]]s, and IDE/[[Rapid Application Development]] (RAD)) in this category:

* [[Turbo Pascal]] – "TURBO.EXE" up to version 7, and Turbo Pascal for Windows ("TPW") and [[Turbo Pascal#Apple Macintosh|Turbo Pascal for Macintosh]].

* [[Pure Pascal]] and [[HiSPeed Pascal]] 2 Pascal language Environment for the [[Atari ST]] range of computers.

* [[Turbo Pascal|Borland Pascal 7]] – A professional version of Turbo Pascal line which targeted both DOS and Windows.

* [[Object Pascal]] – an extension of the Pascal language that was developed at [[Apple Computer]] by a team led by [[Larry Tesler]] in consultation with [[Niklaus Wirth]], the inventor of Pascal; its features were added to Borland's [[Turbo Pascal#Apple Macintosh|Turbo Pascal for Macintosh]] and in 1989 for Turbo Pascal 5.5 for DOS.