🚀 go-pugleaf

pcg@rupert.cs.aber.ac.uk (Piercarlo Grandi) wrote a long note about the
interrelationships of the Algols, Simula, Pascal, etc., but got some of the
history turned about.

Let's pick up about here...
> In Europe, two landmark events happened; Dahl, Dijkstra, Hoare
> authored "Structured Programming"...

You need to be careful about that one, because the three parts of _Struc-
tured_Programming_ have different origins and different real dates.

[vanWijngaarden's work]
> new technology for grammars that could be used to describe
> context sensitive aspects.

There are really two aspects to the work here.  Remember (or note, if you're
fortunate enough not to remember:-) that the original Algol 68 report had
the two-level "vW" grammar, but used ordinary prose to describe "context
conditions".  The revised report (circa 72?) pushed the grammar much
further.

> After Hoare's paper on data typing in "Structure programming"
> Wirth designed a language, called Pascal, that implemented a
> *very small* subset of Hoare's ideas...

This is a bit backwards.  Pascal was first out about 1970; _Structured_
_Programming_ was published after that.  However, Hoare's work is properly
dated more like '65 (it just took a while to see print in _S_P_), and the
work itself certainly laid the basis for Pascal's type structure.  I think
Hoare and Wirth were working closely at that time.

> A small war ensued between the Pascal, Wirth, Hoare, Dijkstra
> camp, and the Van Wijngaarden, Algol 6[68], CPL, camp; Pascal
> was hailed as a theoretically sound language, Algol 68 fans retorted it
> was too simple and limited to be adopted as a general purpose international
> standard.

Pascal was a result of the war, not the precipitator.  There were several
candidate language proposals presented to WG2.1, and after very heated
dispute (Grandi calls it a "small war"; I would omit "small":-), those
favoring a simple language produced a sort of "minority report" and
eventually left the group.  Pascal followed shortly thereafter.

> In the meantime BCPL too, much for the same reasons, had become
> popular, and, thanks to links between Cambridge UK and some USA
> research centers (Xerox, MIT, Bell Labs), had been adopted in
> several parts of that country...

I'd say that BCPL had really become significant *before* the Pascal/
Algol 68 flap...although it was certainly alive and well then.

[moving to another part...]
> About the same time, several people from cambridge UK happened to
> visit Bell Labs, among them S. Bourne, one of the authors of the
> Algol68C (a large subset of algol 68) compiler. This strongly
> influenced the /bin/sh shell syntax (and its implementation),...

That's what we know now as the "Bourne shell" - but this appeared circa
Version 7, which is very late 70's.  The Bourne shell was by no means the
first /bin/sh.

>...the adb debugger,...

Don't forget that there was an Algol 68 implementation for V7 (by Bourne).
According to Bourne, adb was developed to help debug that implementation.

>    I will still argue vigorously that the Pascal family
>    was founded on Algol-60 (consider the relative dates)...
>...Well, if you believe what I said above, Pascal was meant as an
> *alternative* to Algol 60, and as a successor, it had a very
> distinctly different flavour...

Pascal was intended from the start to be a "small" language, and to have a
straightforward mapping onto the machine.  Given that Pascal was first
implemented on CDC 6x00's, and given the grotesque, hideous, abysmal imple-
mentation of Algol 60 on that machine, I wonder what part of Wirth's atti-
tude to Algol 60 as a real language was formed by latter-day experience
with that implementation.

> Other interestiong notes: J. Ichbiah, the Ada man, had previously
> worked a lot on Simula 67, somewhat on Algol 68, and developed an
> implementation language whose ancestry seems to me clearly
> derived from Algol 68 or Mary, called LIS, many of which features
> popped up in Ada. Ada itself also contains a number of ideas
> taken straight from Algol 68...

Anyone seriously designing an algorithmic language post-1970 has to have
been influenced somehow by Algol 68.  I wonder if some of the influences
from Algol 68, and more particularly from Mary (a wonderful bit of work)
could have come via Mark Rain, who was deeply involved in Mary and at least
peripherally involved in both Algol 68 and Green.
-- 
Dick Dunn     rcd@ico.isc.com    uucp: {ncar,nbires}!ico!rcd     (303)449-2870
   ...Never offend with style when you can offend with substance.