Editing Pascal (programming language) (section)

{{short description|Programming language}}
{{other uses|Pascal (disambiguation)}}
{{Infobox programming language
| name = Pascal
| logo = 
| paradigm = {{hlist |[[Imperative programming|Imperative]] |[[Structured programming|structured]]}}
| family = [[Niklaus Wirth|Wirth]] Pascal
| designer = [[Niklaus Wirth]]
| released = {{Start date and age|1970}}
| latest release version = 
| latest release date = 
| typing = {{hlist |[[Static typing|Static]] |[[Strong and weak typing|strong]] |[[type system#Type safety and memory safety|safe]]}}
| scope = [[Scope (computer science)|Lexical]]
| implementations = {{hlist |[[Berkeley Software Distribution|BSD]] |
[[CDC 6000]] |[[Delphi (software)|Embarcadero Delphi]] |[[ICT 1900 series|ICL 1900]] |[[Pascal-P]] |[[PDP-11]] |[[PDP-10]] |[[IBM System/370]] |[[VSI Pascal]] |[[Free Pascal]] |[[GNU Pascal]]}}
| dialects = {{hlist |[[Delphi (software)|Delphi]] |[[Turbo Pascal]] |[[UCSD Pascal]]}}
| influenced by = {{startflatlist}}
* [[ALGOL W]]
* [[Simula]] 67
{{endflatlist}}
| influenced = {{startflatlist}}
* [[Ada (programming language)|Ada]]
* [[C/AL]]
* [[C Sharp (programming language)|C#]]
* [[Component Pascal]]
* [[Go (programming language)|Go]]
* [[Java (programming language)|Java]]<ref>{{cite web| url=http://java.sun.com/docs/white/delegates.html |title=About Microsoft's "Delegates" |archive-url=https://web.archive.org/web/20120627043929/http://java.sun.com/docs/white/delegates.html |archive-date=2012-06-27 |quote=We looked very carefully at Delphi [[Object Pascal]] and built a working prototype of bound method references in order to understand their interaction with the Java programming language and its APIs&nbsp;... Our conclusion was that bound method references are unnecessary and detrimental to the language. This decision was made in consultation with Borland International, who had previous experience with bound method references in Delphi [[Object Pascal]].}}</ref><ref>{{cite web |url=http://www.fscript.org/prof/javapassport.pdf |quote=The project went ahead under the name "green" and the language was based on an old model of [[UCSD Pascal]], which makes it possible to generate interpretive code |title=History of Java |work=Java Application Servers Report |author=TechMetrix Research |date=1999 |url-status=dead |archive-url=https://web.archive.org/web/20101229090912/http://www.fscript.org/prof/javapassport.pdf |archive-date=2010-12-29 |access-date=2009-10-16 }}</ref><ref>{{cite web|url=http://queue.acm.org/detail.cfm?id=1017013|title=A Conversation with James Gosling – ACM Queue|access-date=11 August 2015|url-status=live|archive-url=https://web.archive.org/web/20150716194245/http://queue.acm.org/detail.cfm?id=1017013|archive-date=16 July 2015}}</ref>
* [[Modula]]{{\}}[[Modula-2|-2]]{{\}}[[Modula-3|-3]]
* [[Oberon (programming language)|Oberon]]{{\}}[[Oberon-2|-2]]
* [[Object Pascal]]
* [[Oxygene (programming language)|Oxygene]]
* [[Microsoft Power Fx|Power Fx]]
* [[Seed7]]
* [[Standard ML]]
* [[VHDL]]
* [[Structured text]]
{{endflatlist}}
| operating system = 
| license = 
| website = 
| file_ext = .pas
| wikibooks = Pascal Programming
}}
'''Pascal''' is an [[Imperative programming|imperative]] and [[Procedural programming|procedural]] [[programming language]], designed by [[Niklaus Wirth]] as a small, efficient language intended to encourage good programming practices using [[structured programming]] and [[data structure|data structuring]]. It is named after French mathematician, philosopher and physicist [[Blaise Pascal]].{{efn|In an issue of ''[[Electronics (magazine)|Electronics]]'' in 1978, Wirth explained why he named the language after Blaise Pascal: "Actually, I am neither capable of fully understanding his philosophy nor of appreciating his religious exaltations. Pascal, however, was (perhaps one of) the first to invent and construct [[Pascal's calculator|a device]] that we now classify as a digital computer."<ref>{{cite magazine |last=Wirth |first=Niklaus |author-link=Niklaus Wirth |date=1978-12-21 |title=Obeisance to Pascal, inventor |magazine=[[Electronics (magazine)|Electronics]] |publisher=Dan McMillan |editor1-first=Kemp |editor1-last=Anderson |department=Readers' comments |issn=0013-5070 |url=https://www.worldradiohistory.com/Archive-Electronics/70s/78/Electronics-1978-12-21.pdf |access-date=2024-08-13 |archive-url=https://web.archive.org/web/20240520045053/https://www.worldradiohistory.com/Archive-Electronics/70s/78/Electronics-1978-12-21.pdf |archive-date=2024-05-20 |url-status=live |page=6}}</ref>}}

Pascal was developed on the pattern of the [[ALGOL 60]] language. Wirth was involved in the process to improve the language as part of the [[ALGOL X]] efforts and proposed a version named [[ALGOL W]]. This was not accepted, and the ALGOL X process bogged down. In 1968, Wirth decided to abandon the ALGOL X process and further improve ALGOL W, releasing this as Pascal in 1970.

On top of ALGOL's [[variable (computer science)|scalar]]s and [[array (data type)|arrays]], Pascal enables defining complex datatypes and building dynamic and recursive data structures such as [[list (abstract data type)|list]]s, [[tree (data structure)|tree]]s and [[graph (abstract data type)|graph]]s. Pascal has [[strong and weak typing|strong typing]] on all objects, which means that one type of data cannot be converted to or interpreted as another without explicit conversions. Unlike C (and also unlike most other languages in the [[C-family]]), Pascal allows [[nested procedure]] definitions to any level of depth, and also allows most kinds of definitions and declarations inside [[subroutines]] (procedures and functions). A program is thus syntactically similar to a single procedure or function. This is similar to the block structure of ALGOL 60, but restricted from arbitrary block statements to just procedures and functions.

Pascal became very successful in the 1970s, notably on the burgeoning [[minicomputer]] market. [[Compiler]]s were also available for many [[microcomputer]]s as the field emerged in the late 1970s. It was widely used as a teaching language in [[university]]-level programming courses in the 1980s, and also used in production settings for writing commercial software during the same period. It was displaced by the [[C (programming language)|C programming language]] during the late 1980s and early 1990s as [[UNIX]]-based systems became popular, and especially with the release of [[C++]].

A derivative named [[Object Pascal]] designed for [[object-oriented programming]] was developed in 1985. This was used by [[Apple Inc.|Apple Computer]] (for the [[Apple Lisa|Lisa]] and [[Mac (computer)|Macintosh]] machines) and [[Borland]] in the late 1980s and later developed into [[Delphi (software)|Delphi]] on the [[Microsoft Windows]] platform. Extensions to the Pascal concepts led to the languages [[Modula-2]] and [[Oberon (programming language)|Oberon]], both developed by Wirth.