Editing ALGOL 68S

{{Short description|Programming language}}
{{Infobox programming language
| name = ALGOL 68S
| logo = <!-- Filename -->
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| screenshot = <!-- Filename -->
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| paradigms = [[Multi-paradigm programming language|Multi-paradigm]]: [[Concurrent programming language|concurrent]], [[Imperative programming|imperative]]
| family = [[ALGOL]]
| designer = [[Charles H. Lindsey]]
| developer = <!-- or: | developers = -->
| released = {{Start date and age|1977}}<!-- If known, add |mm|dd|df=yes -->
| latest release version = 
| latest release date = <!-- {{Start date and age|19yy|mm|dd|df=yes}} -->
| typing = [[Type system#Type checking|static]], [[Strong and weak typing|strong]], [[Type system#Safely and unsafely typed systems|safe]], [[Structural type system|structural]]
| scope = [[Scope (computer science)|Lexical]]
| programming language = [[BLISS]]
| discontinued = 
| platform = [[Motorola 68000 series|Motorola 680x0]], Sun [[SPARC]]
| operating system = [[SunOS]], [[Solaris (operating system)|Solaris]], [[Atari ST#Operating system|GEMDOS]]
| license = 
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| website = <!-- {{URL|www.example.com}} -->
| implementations = 
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| influenced by = 
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}}
'''ALGOL 68S''' is a [[programming language]] designed as a subset of [[ALGOL 68]], to allow compiling via a [[one-pass compiler]].<ref name="SIGPLAN">{{cite journal |last=Hibbard |first=P.G. |date=May 1977 |title=A Sublanguage of ALGOL 68 |journal=SIGPLAN Notices |volume=12 |issue=5|pages=71–79 |doi=10.1145/954652.1781177 |s2cid=37914993 |doi-access=free }}</ref> It was mostly for [[numerical analysis]].

==Implementations==
A compiler for ALGOL 68S was available for the [[PDP-11]], written in the language [[BLISS]]. The multiprocessor version designed for the [[C.mmp]]<ref name="Cmmp">{{cite journal |url=http://vestein.arb-phys.uni-dortmund.de/~wb/a68s.txt}} {{Dead link|date=September 2018 |bot=InternetArchiveBot |fix-attempted=yes}} Description of C.mmp A68S implementation.</ref> has been preserved at the PDP Unix Preservation Society archive.<ref>{{cite web |url=http://www.tuhs.org/Archive/PDP-11/Applications/algol68.tar.gz |title=Archived copy |website=www.tuhs.org |access-date=13 January 2022 |archive-url=https://web.archive.org/web/20080720120211/http://www.tuhs.org/Archive/PDP-11/Applications/algol68.tar.gz |archive-date=20 July 2008 |url-status=dead}}</ref>

[[Charles H. Lindsey]] created another implementation of ALGOL 68, named ALGOL 68S, for [[Sun-3]], Sun [[SPARC]] (under [[SunOS]] 4.1), Sun SPARC (under [[Solaris (operating system)|Solaris]] 2), [[Atari ST]] (under [[Atari ST#Operating system|GEMDOS]]) and [[Acorn Archimedes]] (under [[RISC OS]]).

==Chief differences from ALGOL 68==
The main differences between ALGOL 68 and 68S, as summarised from Appendix 4 of the Informal Introduction,<ref name="II">{{cite book |last1=Lindsey |first1=C. H. |author-link=Charles H. Lindsey |last2=van der Meulen |first2=S. G. |date=1977 |title=Informal Introduction to Algol 68 |publisher=North-Holland}}</ref> include:
* No ''union''
* No ''flex'', but ''string''s are handled specially
* No arrays inside structures (but references to arrays were allowed) and a similar restriction on arrays of arrays (multidimensional arrays are nonetheless permitted)
* Limits on use of ''long'' and ''short'' to aid implementing on small computers
* No ''heap''
* No [[Parallel computing|parallel processing]]
* Limits on the order of declaration and other small syntactic differences to allow one-pass compiling
* No ''format''s

==References==
{{Reflist}}

{{ALGOL programming}}

{{DEFAULTSORT:Algol 68s}}
[[Category:ALGOL 68 implementation|Subset]]


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