View source for COWSEL

{{Short description|Programming language}}
{{One source|date=March 2024}}
{{Use dmy dates|date=March 2024}}
{{Use British English|date=March 2024}}
{{Infobox programming language
| name = COWSEL, POP-1
| logo = <!-- Filename only -->
| logo caption = 
| screenshot = <!-- Filename only -->
| screenshot caption = 
| sampleCode = 
| paradigm = [[Programming paradigm|Multi-paradigm]]: [[Structured programming|structured]], [[Reflective programming|reflective]], [[Procedural programming|procedural]]
| family = [[Lisp (programming language)|Lisp]]: POP
| designers = [[Robin Popplestone]], [[Rod Burstall]]
| developers = [[University of Leeds]], [[University of Bradford|Bradford Institute of Technology]], [[University of Edinburgh]]
| released = {{Start date and age|1964}}
| latest release version = 
| latest release date = <!-- {{Start date and age|196?}} -->
| typing = [[Dynamic typing|dynamic]]
| memory management = 
| scope = 
| programming language = [[Assembly language|assembly]]
| platform = [[Ferranti Pegasus]], Stantec Zebra, [[Elliot 4120]]
| operating system = 
| license = [[Proprietary software|Proprietary]]
| file ext = 
| file format = <!-- or: | file formats = -->
| website = <!-- {{URL|}} -->
| implementations = 
| dialects = 
| influenced by = [[CPL (programming language)|CPL]], [[Lisp (programming language)|Lisp]]
| influenced = [[POP-2]]
}}
'''COWSEL''' ('''COntrolled Working SpacE Language''') is a [[programming language]] designed between 1964 and 1966 by [[Robin Popplestone]]. It was based on an [[reverse Polish notation]] (RPN) form of the language [[Lisp (programming language)|Lisp]], combined with some ideas from [[CPL (programming language)|Combined Programming Language]] (CPL).

COWSEL was initially implemented on a [[Ferranti Pegasus]] computer at the [[University of Leeds]] and on a Stantec Zebra at the [[University of Bradford|Bradford Institute of Technology]]. Later, [[Rod Burstall]] implemented it on an [[Elliot 4120]] at the [[University of Edinburgh]].

COWSEL was renamed '''POP-1''' in 1966, during summer, and development continued under that name from then on.

==Example code==
 <u>function</u> member
 <u>lambda</u> x y
 <u>comment</u> Is x a member of list y;
 <u>define</u>      y <u>atom</u> <u>then</u> *0 <u>end</u>
             y <u>hd</u> x <u>equal</u> <u>then</u> *1 <u>end</u>
             y <u>tl</u> -> y <u>repeat</u> <u>up</u>

[[Reserved word]]s (keywords) were also underlined in the original printouts. Popplestone performed [[syntax highlighting]] by using underscoring on a [[Friden Flexowriter]].

==See also==
* [[POP-2]] programming language
* [[POP-11]] programming language
* [[Poplog]] programming environment

==References==
* Technical report: EPU-R-12, U Edinburgh (Apr 1966)

==External links==
* [https://web.archive.org/web/20080906044133/http://hopl.murdoch.edu.au/showlanguage2.prx?exp=196 "The Early Development of POP" on The Encyclopedia of Computer Languages]

{{POP programming}}
{{Lisp programming language}}

[[Category:Functional languages]]
[[Category:Lisp programming language family]]
[[Category:History of computing in the United Kingdom]]
[[Category:Programming languages created in 1964]]
[[Category:Programming languages]]
[[Category:Science and technology in Edinburgh]]
[[Category:University of Bradford]]
[[Category:University of Edinburgh]]
[[Category:University of Leeds]]


{{Prog-lang-stub}}