Path: utzoo!attcan!uunet!mcvax!ukc!dcl-cs!nott-cs!anw
From: anw@nott-cs.UUCP
Newsgroups: comp.lang.misc
Subject: Re: Algol 60 vs Algol 68 (was "stack machines (Burroughs)")
Message-ID: <565@tuck.nott-cs.UUCP>
Date: 20 Jun 88 18:29:38 GMT
References: <1521@pt.cs.cmu.edu> <1532@pt.cs.cmu.edu> <476@pcrat.UUCP> <2868@louie.udel.EDU> <370@dlscg1.UUCP> <3147@polyslo.UUCP> <10064@t
Reply-To: anw@maths.nott.ac.uk (Dr A. N. Walker)
Organization: Department of Mathematics, The University, NOTTINGHAM, NG7 2RD, UK.
Lines: 77

>   == paul@unisoft.UUCP (Paul Campbell) in <1188@unisoft.UUCP>
>>  == bvs@light.UUCP (Bakul Shah) in <1988Jun11.200757.12285@light.uucp>
>>> == Andrew Klossner in <10064@tekecs.TEK.COM>

>>>There really isn't any "beyond" to Algol 68 since the 1975 Revised
>>>Report.  It's a dead language.  And that's too bad; [ ... ]

	Mostly agreed.  Yet there were several good ideas that didn't quite
make it into the 1975RR (modals, partial parametrisation, imported/exported
variables, etc), but were much discussed in Algol Bulletin, and are only
just making it into `modern' languages.  And it's not quite as dead as
most computing scientists might think.  We still have several large
applications running on the Univ mainframe;  I still use it on our
PDP 11/44 [only language available with semaphores, :-(].  Sadly, it will
probably die locally if we ever manage to upgrade our hardware.

>>I wonder how much of C design was influenced by Algol 68 as most
>>of K&R C seems to map almost directly to Algol 68 [...]

	Well yes, but almost any algorithmic language mostly maps pretty
directly to Algol 68.  Only K&R could tell you exactly how much K&R were
influenced by Algol 68;  some things probably were (assignment operators),
some things obviously weren't (for statements), and some things ought to
have been more so (unification of expressions and statements).

>>						       [...]  Come
>>to think of it, a major subset of Algol 68 with a new and concise
>>syntax (sort of like C's) ...

	What?  The *full* syntax of A68 fits easily as structure diagrams
into one side of A4 (the `Watt-Peck-Sintzoff' diagram), or as sort-of
BNF rules into a side-and-a-bit (Woodward and Bond rules).  Both A68 and
its syntax are more concise than C;  that was the source of many people's
complaints over the years.

>>			... can make a very elegant, type safe and
>>well rounded language.

	Yeah!

>  Probably the main success story from the Algol 68 effort was Pascal, Wirth
>was one of Algol 68's designers (he was on the committee) and in Pascal he
>implemented all the things in Algol 68 (plus a few extras) that were easy
>to implement using the existing technology, the result was a language that
>flourished ....

	Which committee?  There were lots.  I don't think Wirth (or many of
the other `survivors' from the Algol 60 days) had much affinity with A68
as it emerged.  The developing schisms, as reported in Algol Bulletin, make
highly entertaining reading, and make anything we've seen on the Net about
C or Fortran standardisation look like a vicarage tea party.  If Wirth had
indeed made Pascal an easily implemented A68, we would all be deeply in his
debt.  Unfortunately, Pascal was a clear step back in language design;
and also now a moribund language.

	Examples of easily implemented A68 features that didn't make it
into Pascal:

	Assignment operators
	Generalised FOR statement
	Closures
	Initialised declarations
	Declarations "as needed" instead of in a rigid format at top of block
	Complex numbers
	Dynamic arrays, and other array features such as UPB
	SKIP (visible empty statement)
		etc, etc.

	IMHO, the Algol thread of language development could be revived, if
only someone, somewhere, had a compiler, any compiler, that they were willing
to make freely and widely available, eg on the Net.  Pascal flourished
because compilers and books about it were made easily available.  A68 has
the books (just about), but not the compilers.

-- 
Andy Walker, Maths Dept., Nott'm Univ., UK.
anw@maths.nott.ac.uk