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Neither Algol 60 nor Algol 68 were very good choices, but it was basically them or FORTRAN which were used back then in published algorithms. Algol 60 was the forbearer of most modern programming languages. However, implementations of Algol 60 were all a bit different and even after the the revised report came out a few years later there remained serious ambiguities in the meaning of common Algol 60 constructs, see for example [1]. Other aspects of Algol 60, for example the use of call-by-name argument passing semantics, made it not entirely suitable
as a means of communicating algorithms. Algol 68, had, for many years, essentially no conforming implementations. The language was remarkably orthogonal, every aspect seemed to be fully generalized and usable everywhere in the language, but it was too complicated. At least, it had a concept of I/O, which Algol 60 lacked. Some algorithms were published in Algol 68, but I didn't see many of them. In this environment, Knuth's books were quite valuable. The algorithms, while not structured or written as we see them now were clear and unambiguous and were written for a time when compilers didn't perform advanced code-optimizations; Knuth's careful designs included optimizations that we would leave to compilers today when talking about algorithms. Eventually, Pascal came along and it became possible to publish algorithms in an easy to read and unambiguous way. (It was still uncommon to see code formatted in any consistent way. See Wirth's own books!) Pascal wasn't perfect, but it was easy to understand and implementations were portable and widely available. [1] Knuth, The remaining trouble spots in Algol 60*, https://atlas.cs.virginia.edu/~asb/teaching/cs415-fall05/doc... |