Re: Is there a language that Dijkstra liked? (was: Re: Software landmines (loops))

[Matthew Heaney <matthew_heaney@acm.org>]

dewarr@my-dejanews.com writes:

> In article <3600E72E.24C93C94@cl.cam.ac.uk>,
>   Markus Kuhn <Markus.Kuhn@cl.cam.ac.uk> wrote:
> 
> > I thought that Dijkstra wrote years after his famous criticism on Ada,
> > which basically killed interest on Ada in the academic community for
> > many years, a quite nice foreword for an Ada 83 textbook by Jean Ichiba.
> 
> Perhaps you are talking about AH's Turing address, which
> certainly did not "kill interest on Ada in the academic
> community" [after all at least two major Ada vendors playing
> today have their roots in academic research efforts]. AH did
> also write a nice forward for a book by Brian Wichman.

I have to disagree with you, Robert.  It is my opinion that it was
Hoare's Turing Award speech that single-handedly derailed the Ada
language effort.  He essentially argued that by using Ada, "the fate of
mankind" was at stake.  

People listened to him.  Lots of people listened to him.  To this day,
people still quote the Hoare speech (among them, Bertrand Meyer) in
order to back up their own criticisms of Ada.  (The argument goes
something like, "See, Tony Hoare said Ada was bad, so it must be so.")

It's the kind of thing that probably prompted C.B. Jones to remark that:

"Subsequent to this publication, Hoare and Wirth consulted for SRI on
their 'Yellow' language response to the 'Tinman' requirements.  Their
consistent advice to simplify even this language was unheeded - but the
final Ada language (the 'Green' proposal) was even more baroque."

(excerpted from Chap 13, "Hints on programming language design", in
Essays in Computing Science, by Hoare and Jones).

In his speech, Hoare argued that "Ada was doomed to succeed."  This
hardly sounds like a hearty endorsement.  And his tepid remarks in the
forward of David Watt's book seem only perfunctory.
 
> If it is really this that you are referring to, please check
> facts -- it is easy to see how urban legends get established
> :-)
> 
> EWD did write criticisms of the four colored languages, but
> actually I found these criticisms fairly mild, basically he
> gave the impression that he generally liked this sort of
> level of language, but had nits to pick with each of the
> colors!

Again, my reading of his critique is quite different from yours.  In his
summary of the DoD-I language effort, Dijkstra writes:

<<My overwhelming impression is that, in particular in combination with
the Revised IRONMAN Requirements ... the compstitive situation in hich
the four design groups had been placed, had been disastrous.  Instead of
trying to design the most adequate programming language, they have all
four tried to get the next contract, and that is a completely different
thing!...

Firstly the four reports I studied were all an almost inextricable
mixture of technical documentation and salestalk, and that made their
study unnecessarily difficult and unpleasant.  It made the reading
unpleasant because quite often the saletalk was so close to dishonesty
or nonsense that my ability to approach the design with feelings of
sympathy was severely strained.>>

The rest of the paper lists some valid criticisms of the IRONMAN
Requirements.  (His comments really apply to the specification of any
set of requirements, so they make a good read.)

Towards the end he recalls the text of a letter he sent to a friend re
his reviews:

<<"... But I was not propared for such junk as I have seen.  Isn't this world a
disappointing, depressing place?  Do these people not know how much care
such a design requires?...

"I have now done two of them [reviews of the languages], but need one or
two days off, to collect some courage, before I dare embark on the
third."

In his answer [to Dijkstra's letter] he discussed the phenomenon that,
compared to PASCAL (with all its imperfections and shortcomings taken
into account), the proposed languages are such a gigantic step
backwards.>>

He concludes by saying that 

<<And this concludes a month of most depressing work.  Why does the
world seem to persist so stubbornly in being such a backward place?  Why
do people refuse to learn from the past and why do they persist in
making the known and well-identified mistakes again?  It is all very
saddening.

Of ALGOL 60 C.A.R. Hoard once remarked that it was a significant
improvement over almost all of its successors.  What can we do to
prevent PASCAL from sharing that fate?>>


I would argue that Dijkstra's comments comprised more than mere "nits."