View source for Turing (programming language)

{{Short description|High-level computer programming language}}
{{Infobox programming language
| name = Turing
| logo = [[File:Turing logo.gif]]
| paradigm = multi-paradigm: [[Object-oriented programming|object-oriented]], [[Procedural programming|procedural]]
| year = 1982
| designer = Ric Holt and [[Biography:James Cordy|James Cordy]]
| developer = Holt Software Associates
| latest_release_version = <!--X.Y.Z/{{release date|mf=yes|YYYY|MM|DD}}-->
| latest release date =
| typing = static, [[Manifest typing|manifest]]
| implementations = Turing, TPlus, OpenT
| dialects =  Object-Oriented Turing, Turing Plus
| influenced_by =[[Euclid (programming language)|Euclid]], [[Pascal (programming language)|Pascal]], SP/k
| influenced =
| operating_system = [[Software:Microsoft Windows|Microsoft Windows]]
| license =
| website =
| file_ext =
}}

'''Turing''' is a [[High-level programming language|high-level]], [[General-purpose programming language|general-purpose programming language]] developed in 1982 by Ric Holt and [[Biography:James Cordy|James Cordy]], at [[Organization:University of Toronto|University of Toronto]] in Ontario, Canada. It was designed in order to help students taking their first computer science course learn how to code. Turing is a descendant of [[Pascal (programming language)|Pascal]], [[Euclid (programming language)|Euclid]], and SP/k that features a clean syntax and precise machine-independent semantics.

Turing 4.1.0 is the latest stable version of Turing. Turing 4.1.1 and Turing 4.1.2 does not allow stand alone .exe files to be created and versions before Turing 4.1.0 have outdated syntax and outdated functions.

==Overview==
Named after British computer scientist [[Biography:Alan Turing|Alan Turing]], Turing is used primarily as a teaching language at the high school and university level.<ref>Fluck, A., Webb, M., Cox, M., Angeli, C., Malyn-Smith, J., Voogt, J., & Zagami, J. (2016). Arguing for computer science in the school curriculum. ''Journal of Educational Technology & Society, 19''(3), 38-46.</ref> Two other versions exist, Object-Oriented Turing and Turing Plus, a systems programming variant. In September 2001, "Object Oriented Turing" was renamed "Turing" and the original Turing was renamed "Classic Turing". Turing is no longer supported by Holt Software Associates in Toronto, Ontario. Turing was widely used in high schools in Ontario as an introduction to programming.<ref>{{Cite web|url=http://compsci.ca/holtsoft/|title=Download Turing & RTP (Ready to Program)|last=info@compsci.ca|website=compsci.ca|access-date=2018-08-21}}</ref>

On November 28, 2007, Turing, which was previously a commercial programming language, became freeware, available to download from the developer's website free of charge for personal, commercial, and educational use.<ref name=holtsoft>{{cite web|url=http://www.holtsoft.com|title=Holt Software Associates Home Page|date=January 2008|access-date=2010-04-10|url-status=dead|archive-url=https://web.archive.org/web/20100405101149/http://www.holtsoft.com/|archive-date=2010-04-05}}</ref><ref name="holtsoft/old_index">{{cite web|url=http://www.holtsoft.com/old_index.html|title=Holt Software Associates Home Page (old)|date=2007-11-25|access-date=2010-04-10|url-status=dead|archive-url=https://web.archive.org/web/20100417185823/http://www.holtsoft.com/old_index.html|archive-date=2010-04-17}}</ref><ref>{{Cite web |url= http://compsci.ca/blog/download-turing-411/|title= Download Turing 4.1.1|access-date= 2009-01-10|publisher= compsci.ca Blog|date= 2007-11-28}}</ref>

The makers of Turing, Holt Software Associates, have since ceased operations, and Turing has seen no further development since November 25, 2007.<ref name="holtsoft/old_index"/>

==Syntax==
Turing is designed to have a very lightweight, readable, intuitive syntax. Here is the entire Hello World! program in Turing with [[Syntax highlighting|syntax highlighting]]:

 '''put''' <span style="color:red">"Hello World!"</span>

Turing avoids semicolons and braces, using explicit end markers for most language constructs instead, and allows declarations anywhere. Here is a complete program defining and using the traditional [[Recursion|recursive]] function to calculate a [[Factorial|factorial]].

  <span style="color:green">*comment*% Accepts a number and calculates its factorial</span>
  
  '''function''' <span style="color:blue">factorial</span> (<span style="color:blue">n</span>: '''int''') : '''real'''
       '''if''' <span style="color:blue">n</span> = 0 '''then'''
            '''result''' 1
       '''else'''
            '''result''' <span style="color:blue">n</span> * <span style="color:blue">factorial</span> (<span style="color:blue">n</span> - 1)
       '''end if'''
  '''end''' <span style="color:blue">factorial</span>
  
  '''var''' <span style="color:blue">n</span>: '''int'''
  '''loop'''
       '''put''' <span style="color:red">"Please input an integer: "</span> ..
       '''get''' <span style="color:blue">n</span>
       '''exit when''' <span style="color:blue">n</span> >= 0
       '''put''' <span style="color:red">"Input must be a non-negative integer."</span>
  '''end loop'''
  
  '''put''' <span style="color:red">"The factorial of "</span>, <span style="color:blue">n</span>, <span style="color:red">" is "</span>, <span style="color:blue">factorial</span> (<span style="color:blue">n</span>)

==Open implementations==

Currently, there are two open source alternative implementations of Turing: Open Turing, an open source version of the original interpreter, and TPlus, a native compiler for the concurrent systems programming language variant Turing Plus. OpenT, a project to develop a compiler for Turing, is no longer in development.

===Open Turing===

Open Turing is an open-source implementation of the original Turing interpreter for Windows written by Tristan Hume. It includes speed improvements, new features such as OpenGL 3D and a new code editor. It is fully backwards compatible with the closed-source implementation.<ref>{{cite web|last=Hume|first=Tristan|title=Open Turing|url=http://tristan.hume.ca/openturing/|access-date=6 May 2012}}</ref>

===TPlus===
TPlus is an open-source implementation of original (non-Object-Oriented) Turing with systems programming extensions developed at the University of Toronto and ported to Linux, Solaris and Mac OS X at Queen's University in the late 1990s.<ref>{{cite web|last=Cordy|first=James|title=Turing+ 6.1|url=http://txl.ca/txl-tplusdownload.html|access-date=11 December 2020}}</ref>  TPlus implements Turing+ (Turing Plus), a concurrent systems programming language based on the original Turing programming language. Some, but not all, of the features of Turing Plus were eventually subsumed into the present Object-Oriented Turing language. Turing Plus extends original Turing with [[Process (computing)|processes]] and [[Monitor (synchronization)|monitors]] (as specified by C.A.R. Hoare) as well as language constructs needed for systems programming such as binary input-output, separate compilation, variables at absolute addresses, type converters and other features.

== Turing+ ==
{{Infobox programming language
| name = Turing+
| logo =
| paradigm = multi-paradigm: [[Object-oriented programming|object-oriented]], [[Procedural programming|procedural]], concurrent
| year = 1987
| designer = Ric Holt and [[Biography:James Cordy|James Cordy]]
| developer = Ric Holt and [[Biography:James Cordy|James Cordy]]
| latest_release_version = <!--X.Y.Z/{{release date|mf=yes|YYYY|MM|DD}}-->
| latest release date =
| typing = static, [[Manifest typing|manifest]]
| implementations = 
| dialects =  
| influenced_by =[[Concurrent Euclid]], Turing
| influenced =Object-Oriented Turing
| operating_system =
| license =
| website =
| file_ext =
}}

'''Turing+''' (Turing Plus) is a concurrent systems programming language based on the Turing programming language designed by [[Biography:James Cordy|James Cordy]] and Ric Holt, then at the [[Organization:University of Toronto|University of Toronto]], Canada, in 1987.  Some, but not all, of the features of Turing+ were eventually subsumed into Object-Oriented Turing.  Turing+ extended original Turing with processes and [[Monitor (synchronization)|monitor]]s (as specified by C.A.R. Hoare) as well as language constructs needed for systems programming such as binary input-output, separate compilation, variables at absolute addresses, type converters and other features.

Turing+ was explicitly designed to replace Concurrent Euclid in systems-programming applications.  The [[Software:TUNIS|TUNIS operating system]], originally written in Concurrent Euclid, was recoded to Turing+ in its MiniTunis implementation.  Turing+ has been used to implement several production software systems, including the TXL programming language.

== Object-Oriented Turing ==
{{Infobox programming language
| name =Object-Oriented Turing
| logo =
| paradigm = multi-paradigm: [[Object-oriented programming|object-oriented]], [[Procedural programming|procedural]], concurrent
| year =1991
| designer =Ric Holt
| developer =Ric Holt
| latest_release_version = <!--X.Y.Z/{{release date||YYYY|MM|DD}}-->
| latest release date =
| typing = static, [[Manifest typing|manifest]]
| implementations =
| dialects =
| influenced_by =Turing
| influenced =
| operating_system = Cross-platform: Sun-4, [[MIPS architecture|MIPS]], [[IBM System p|RS-6000]]
| license =
| website =
| file_ext =
}}

'''Object-Oriented Turing''' is an extension of the Turing programming language and a replacement for Turing Plus created by Ric Holt<ref>{{cite journal |last= Mancoridis|first= S |author2=Holt, R C |author3=Penny, D A |date=February 1993|title= A Conceptual Framework for Software Development|journal= ACM Annual Computer Science Conference (SIGCSE, Indianapolis)|pages= 74–80|oclc= 194807519|issn= 1041-4517|id= BL Shelfmark 0578.623000|author2-link= Ric Holt }}</ref><ref>{{cite book |title= Turing reference manual|last= Holt|first= RC|edition= 3rd.|year= 1992|publisher= Holt Software Associates|location= Toronto|isbn= 978-0-921598-15-2|oclc= 71476276}}</ref> of the [[Organization:University of Toronto|University of Toronto]], Canada, in 1991. It is [[Imperative programming|imperative]], [[Object-oriented programming|object-oriented]], and [[Concurrency (computer science)|concurrent]]. It has modules, classes, single [[Inheritance (object-oriented programming)|inheritance]], [[Process (computing)|processes]], [[Exception handling|exception handling]], and optional machine-dependent programming.

There is an [[Integrated development environment|integrated development environment]] under the [[Software:X Window System|X Window System]] and a demo version.{{citation needed|date=October 2013}} Versions exist for Sun-4, [[MIPS architecture|MIPS]], [[IBM System p|RS-6000]], [[Software:NeXTSTEP|NeXTSTEP]], [[Software:Windows 95|Windows 95]] and others. 

==References==
{{Reflist}}

==Further reading==
*{{cite book |last=Grogono |first=Peter |date=1995 |title=Programming with Turing and Object Oriented Turing |url=https://www.springer.com/gp/book/9780387945170 |publisher=Springer-Verlag|isbn=978-0-387-94517-0 }}
*{{cite journal |title= The Turing language report|last1= Holt|first1= Richard C|last2= Cordy|first2= James R|journal= Annual Progress Report|author-link2= James Cordy|date=December 1983|publisher= Computer Systems Research Institute, [[Organization:University of Toronto|University of Toronto]] | location=Canada |issn= 0316-6295}}
*{{cite journal |last= Holt|first= Richard C|author2=Cordy, James R |author-link2=James Cordy |date=December 1988|title= The Turing programming language|journal= [[Communications of the ACM]]|volume= 31|issue= 12|pages= 1410–1423|doi=10.1145/53580.53581|s2cid= 40859457|doi-access= free}}
*{{cite book |title= The Turing programming language: design and definition|last1= Holt|first1= Richard C|last2= Matthews|first2= Philip A|last3= Rosselet|first3= J Alan|last4= Cordy|first4= James R|author-link4= James Cordy|year= 1988|publisher= Prentice Hall|location= Englewood Cliffs, N.J.|isbn= 978-0-13-933136-7|oclc= 17377539}}

==External links==
* {{github|Open-Turing-Project/OpenTuring}}


[[Category:Academic programming languages]]
[[Category:Algol programming language family]]
[[Category:Educational programming languages]]
[[Category:Statically typed programming languages]]
[[Category:Structured programming languages]]

{{Sourceattribution|Turing (programming language)}}