Editing COMAL (section)

===Minicomputer versions===
COMAL was originally developed in [[Denmark]] by mathematics teacher Børge R. Christensen. The school in which he taught had received a [[Data General Nova]] 1200 minicomputer in 1972, with the expectation that the school would begin to teach [[computer science]]. Christensen, who had taken a short course on the subject at university, was expected to lead the program and to maintain the computer system.{{sfn|Christensen|1985|p=1}}

The NOVA was supplied with [[Data General Extended BASIC]], and Christensen quickly became frustrated with the way in which the unstructured language led students to write low-quality code that was difficult to read and thus mark.{{sfn|Christensen|1985|p=1}} While complaining about these problems to computer scientist Benedict Løfstedt, Løfstedt encouraged Christensen to read ''[[Systematic Programming]]'', the then-new book on programming language design by [[Niklaus Wirth]], the creator of [[Pascal (programming language)|Pascal]]. Christensen was impressed, but found that he could not use Pascal directly, as it lacked the interactive [[shell (computing)|shell]] that made BASIC so easy for students to develop with.{{sfn|Christensen|1985|p=2}}

Over the next six months Christensen and Løfstedt corresponded by mail to design an alternative to BASIC which retained its interactive elements but added structured elements from Pascal.{{sfn|Christensen|1985|p=2}} By 1974, the language's definition was complete but Christensen was unsuccessful in attracting interest from software firms in developing an implementation. Over the next six months he worked with two of his students, to whom he had taught NOVA 1200 [[machine language]], to write an implementation themselves. One of the first things added was the ability to use eight-character variable names, up from the typical one or two.{{sfn|Christensen|1985|p=2}} Later additions in the first version included multi-line {{code|IF...THEN...ELSE...ENDIF|comal}} statements, and the {{code|PROC...ENDPROC|comal}} definitions and the {{code|EXECUTE}} statement to call them.{{sfn|Christensen|1985|p=4}}

The first proof-of-concept implementation (running a five-line loop) was ready on 5 August 1974, and the first release (on [[punched tape|paper tape]]) was ready in February 1975. Development costs had been around {{USD|300}}. Only now did the system (which had previously used an internal Danish name) pick up the name ''COMAL'', for ''Common Algorithmic Language'', inspired by [[ALGOL]], with which Christensen had been experimenting.{{sfn|Christensen|1985|p=4}} The first release was therefore named ''COMAL 75''. Christensen subsequently wrote a textbook on the language which evolved into ''Beginning COMAL''.<ref name="The Story of COMAL" />