COMAL

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COMAL
Paradigm structured
Designed by Benedict Løfstedt and Børge R. Christensen
First appeared 1973
Typing discipline strong
Influenced by
BASIC, Pascal

COMAL (Common Algorithmic Language) is a computer programming language developed in Denmark by Benedict Løfstedt and Børge R. Christensen in 1973. COMAL was one of the few structured programming languages that was available for and comfortably usable on 8-bit home computers.

The "COMAL Kernel Syntax & Semantics"[1] contains the formal definition of the language. Further extensions common to many implementations are described in.[2][3][4]

Design[edit]

COMAL was created as a mixture of the prevalent educational programming languages of the time, BASIC, Pascal, and, at least in the Commodore and Compis versions, the turtle graphics of Logo. The language was meant to introduce structured programming elements in an environment where BASIC would normally be used.

With the benefit of hindsight, COMAL looks like a Structured BASIC that has reasonably well-written, vendor neutral, free, standards. It is never necessary to use GOTO, and line numbers are purely for editing purposes rather than flow control. Note, however, that the standardised language only supports control structuring, not data structuring such as records or structs (commercial implementations such as UniCOMAL 3 supported this as an extension).

History[edit]

In the early 1980s, Apple Computer won a contract to supply Apple II computers running CP/M and COMAL to Irish secondary schools.[5] It was popular for education[6] and some textbooks were locally written.[7][8]

In 1984 Acornsoft released a COMAL implementation, by David Christensen, Jim Warwick and David Evers, for their 8-bit BBC Micro and Acorn Electron computers (with a manual by Paul Christensen and Roy Thornton[9])

Between 1984-1987 TeleNova, a subsidiary of the industrial arm of the Swedish Telecoms system, Teli industrier manufactured a desktop PC called "Compis" for the educational sector. An enhanced version of COMAL was supplied as the standard programming language for this PC. Versions were created for both CP/M86 and MS-DOS. The latter version is available for Windows XP. The (Swedish) reference manual is ISBN 91-24-40022-X

In 1990 Thomas Lundy and Rory O'Sullivan produced the definitive text on COMAL Programming.[8] They matched and compared COMAL with BBC Structured Basic.

As of 2016 COMAL is still actively in use as an educational programming language. Some high schools in the United Kingdom continue to use it to teach the subject of Computing.

Availability[edit]

COMAL was historically available for:

however the only maintained implementation seems to be:

Examples[edit]

Conditions:

 IF condition THEN
   instructions
 ENDIF

Loops:

 FOR number:= 1 TO 1000 DO   
  PRINT number
 ENDFOR

Print statements with variables:

 INPUT "What's your favourite number? " :nmr#
 PAGE
 PRINT "Your favourite number is " ; nmr#

"Hello, world!"[edit]

10 PAGE
20 FOR number:= 1 TO 10 DO
30  PRINT "HELLO, WORLD!"
40 ENDFOR
50 END " "

Further reading[edit]

See also[edit]

References[edit]

  1. ^ Ryan, Kevin. "COMAL Kernel Syntax & Semantics". DDHFwiki. Dansk Datahistorisk Forening. Retrieved 8 November 2017. 
  2. ^ Bain, Richard; Lindsay, Len. "Common COMAL Definition and Tests" (PDF). COMAL Today (24): 21–46. Retrieved 8 November 2017. 
  3. ^ "Common COMAL -- Compatible keywords" (PDF). COMAL Today (25): 28. Retrieved 4 April 2018. 
  4. ^ "Common COMAL -- Keyword syntax and examples" (PDF). COMAL Today (25): 29–33. Retrieved 4 April 2018. 
  5. ^ Moynihan, Michael D. (8 August 1983). "COMAL coverage out of Ireland". InfoWorld. 5 (32): 30. Retrieved 15 November 2017. 
  6. ^ Brady, Michael P. (May 1986). The Design of a First Course in Programming. Loughborough, Leicester, UK: Loughborough University of Technology. Retrieved 15 November 2017. 
  7. ^ Kelly, John (1984). Foundations in Computer Studies with COMAL (PDF) (Second ed.). Dublin, Ireland: The Educational Company. Retrieved 15 November 2017. 
  8. ^ a b Lundy, Thomas; O'Sullivan, Rory (1990). Beginning structured programming in BASIC and COMAL. Dublin, Ireland: Gill and Macmillan. ISBN 978-0717116676. 
  9. ^ Thorton, Roy; Christensen, Paul (1984). Comal on the B. B. C. Microcomputer and Acorn ELECTRON SBD 19. Acornsoft. ISBN 978-0907876908. 

External links[edit]