While reading the Byte sieve article (Gilbreath 1981), I came across a language I have never heard of, ZSPL.

I suspected this was actually a specific version of another language, perhaps PL/1. However, the listing shows it most closely resembling Algol/Pascal.

Has anyone heard of this language before? It does not appear on the wiki nor the taxonomies of languages that I can find.

I have seen references to similar names, but they are not related: there is a zSPL system for programming the C64's SID and another for NonStop systems.

  • 1
    It looks Algol-ish, but curiously it has no Boolean type, nor built-in true/false constants. It has a 'printf' which may indicate it's post-Algol 68 (the first language I know with a procedure called 'printf', as distinct from built-in features like Fortran formats). On the other hand, decimal conversion is "%d" like C, and CR-LF is "&M&J", not like C (and implying ASCII). May 2 '19 at 11:53
  • Could you put a link in the question? It also sounds like some sample code is available; that would also be useful in the question.
    – DrSheldon
    May 2 '19 at 11:58
  • 1
    I recommend reading page 198.
    – JdeBP
    May 2 '19 at 11:58
  • Looks a lot like PLZ/SYS, which was a systems programming language from Zilog. Back in the day, I did a lot of work on Z8000 Unix systems, and I remember the PLZ manual coming with each one. It looked like a cool language but I never had a need to use it.
    – mannaggia
    May 2 '19 at 14:00
  • 1
    Looks like a home brew language that didn't take off - pg 198 has a reference to ZSPL - Peter D Ridley, 3321 Byron St, San Diego, CA 92106. Looks like the home address of the inventor of the language at that time.
    – cup
    May 2 '19 at 14:47

Page 198 of that Byte says ZSPL is by Pete Ridley, whose full name appears to be Peter D Ridley, resident at the time in San Diego, California. He and ZSPL are also briefly mentioned in the December 1981 Byte, but I can't find any other trace of them.

However, the sample ZSPL code looks rather like the SPL/3000 programming language, introduced in 1972 by Hewlett-Packard for the HP 3000 business minicomputer. It's lowercase, rather than uppercase, and has some extra keywords. I suspect, although I cannot prove, that ZSPL was an enhanced re-implementation by Ridley of SPL for the Z80 running CP/M, and the "Z" is just from Z80.

  • 1
    Indeed, it looks like ZSPL is simply a Z-80 implementation, the syntax appears almost identical. Well spotted! May 2 '19 at 16:19
  • 1
    The logic went "Z doesn't look like the start of an acronym for that period, try SPL as a programming language." There are several, but only SPL/3000 was the right period, and a look at the manual made the idea look very plausible. May 2 '19 at 17:17
  • 2
    And HP has a history of programming languages matching ?PL :)
    – hobbs
    May 2 '19 at 21:32

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