Turing (programming language)

High-level computer programming language

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TuringFile:Turing logo.gif

Paradigm| multi-paradigm: object-oriented, procedural
Designed by| Ric Holt and James Cordy
Developer| Holt Software Associates
First appeared| 1982
Typing discipline| static, manifest
OS| Microsoft Windows
Major implementations
Turing, TPlus, OpenT
Dialects
Object-Oriented Turing, Turing Plus
Influenced by
Euclid, Pascal, SP/k

Turing is a high-level, general-purpose programming language developed in 1982 by Ric Holt and James Cordy, at 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, 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4.1.1 and Turing 4.1.2 does not allow stand alone (.EXE) files to be created and versions before Turing 4.1.0 have outdated syntax and outdated functions.

## Contents

* 1 Overview
* 2 Syntax
* 3 Open implementations
* 3.1 Open Turing
* 3.2 TPlus
* 4 Turing+
* 5 Object-Oriented Turing
* 6 See also
* 7 References
* 8 Further reading
* 9 External links

## Overview[edit | edit source]

Named after British computer scientist Alan Turing, Turing is used primarily as a teaching language at the high school and university level.[1] 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. Currently, Microsoft Windows is the only supported platform. Turing is widely used in high schools in Ontario as an introduction to programming.[2]

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.[3][4][5]

The makers of Turing, Holt Software Associates, have since ceased operations, and Turing has seen no further development since November 25, 2007.[4]

## Syntax[edit | edit source]

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

put "Hello World!"

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 recursive function to calculate a factorial.

*comment*% Accepts a number and calculates its factorial

function factorial (n: int) : real
if n = 0 then
result 1
else
result n * factorial (n - 1)
end if
end factorial

var n: int
loop
put "Please input an integer: " ..
get n
exit when n >= 0
put "Input must be a non-negative integer."
end loop

put "The factorial of ", n, " is ", factorial (n)

## Open implementations[edit | edit source]

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[edit | edit source]

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.[6]

### TPlus[edit | edit source]

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.[7] 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 processes and 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+[edit | edit source]

Turing+

Paradigm| multi-paradigm: object-oriented, procedural, concurrent
Designed by| Ric Holt and James Cordy
Developer| Ric Holt and James Cordy
First appeared| 1987
Typing discipline| static, manifest
Influenced by
Concurrent Euclid, Turing
Influenced
Object-Oriented Turing

Turing+ (Turing Plus) is a concurrent systems programming language based on the Turing programming language designed by James Cordy and Ric Holt, then at the 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 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+ was explicitly designed to replace Concurrent Euclid in systems-programming applications. The 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[edit | edit source]

Object-Oriented Turing

Paradigm| multi-paradigm: object-oriented, procedural, concurrent
Designed by| Ric Holt
Developer| Ric Holt
First appeared| 1991
Typing discipline| static, manifest
OS| Cross-platform: Sun-4, MIPS, RS-6000
Influenced by
Turing

Object-Oriented Turing is an extension of the Turing programming language and a replacement for Turing Plus created by Ric Holt[8][9] of the University of Toronto, Canada, in 1991. It is imperative, object-oriented, and concurrent. It has modules, classes, single inheritance, processes, exception handling, and optional machine-dependent programming.

There is an integrated development environment under the X Window System and a demo version.[citation needed] Versions exist for

Sun-4, MIPS, RS-6000, NeXTSTEP, Windows 95 and others.

## See also[edit | edit source]

* Euclid (programming language)
* Concurrent Euclid
* TXL

## References[edit | edit source]

1. ^ 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.
2. ^ info@compsci.ca. "Download Turing & RTP (Ready to Program)". compsci.ca. Retrieved 2018-08-21.
3. ^ "Holt Software Associates Home Page". January 2008. Archived from the original on 2010-04-05. Retrieved 2010-04-10.
4. ^ a b "Holt Software Associates Home Page (old)". 2007-11-25. Archived from the original on 2010-04-17. Retrieved 2010-04-10.
5. ^ "Download Turing 4.1.1". compsci.ca Blog. 2007-11-28. Retrieved 2009-01-10.
6. ^ Hume, Tristan. "Open Turing". Retrieved 6 May 2012.
7. ^ Cordy, James. "Turing+ 6.1". Retrieved 11 December 2020.
8. ^ Mancoridis, S; Holt, R C; Penny, D A (February 1993). "A Conceptual Framework for Software Development". ACM Annual Computer Science Conference (SIGCSE, Indianapolis): 74–80. ISSN 1041-4517. OCLC 194807519. BL Shelfmark 0578.623000.
9. ^ Holt, RC (1992). Turing reference manual (3rd. ed.). Toronto: Holt Software Associates. ISBN 978-0-921598-15-2. OCLC 71476276.

## Further reading[edit | edit source]

* Holt, Richard C; Cordy, James R (December 1983). "The Turing language report". Annual Progress Report. Canada: Computer Systems Research Institute, University of Toronto. ISSN 0316-6295.
* Holt, Richard C; Cordy, James R (December 1988). "The Turing programming language". Communications of the ACM. 31 (12): 1410–1423. doi:10.1145/53580.53581. S2CID 40859457.
* Holt, Richard C; Matthews, Philip A; Rosselet, J Alan; Cordy, James R (1988). The Turing programming language: design and definition. Englewood Cliffs, N.J.: Prentice Hall. ISBN 978-0-13-933136-7. OCLC 17377539.
* Grogono, Peter (1995). Programming with Turing and Object Oriented Turing. Springer-Verlag. ISBN 978-0-387-94517-0.

## External links[edit | edit source]

Wikibooks has a book on the topic of: Turing

* Forum for Turing Help, Tutorials, & Source Code
* Github page for the Open Turing project