Re: The making of compilers

["John H. Lindsay" <jlindsay@kingston.net>]

Hi folks:

Robert Dewar wrote:
> 
> Keith Thompson <kst@cts.com> wrote in message news:<yecelj5c7uh.fsf@king.cts.com>...
> > I would have thought that Cobol was a poor language for
> > implementing a compiler, but Robert Dewar and others
> > apparently did just that with Realia Cobol.
> 
> My guess is that Keith is not a COBOL expert :-) Seriously
> usually this kind of opinion comes from people who do not
> know COBOL well. COBOL is a general purpose language with
> many attractive features, and is perfectly suitable for
> writing compilers.
.....

I'll take Robert's word on this due to his direct experience 
with using COBOL for this and wide experience with compilers 
in general, but OTOH I have to say that it's possible to 
botch even the best choice-of-language situations with bad 
programming.  My case in point is the Burroughs Large 
Systems GPSS compiler, coded in Burroughs COBOL, a most 
difficult choice due to the capabilities of the (B) COBOL 
and some other COBOLs at that time (1975..1980).  (All the 
other (B) compilers, as far as I know, were written in (B) 
Algol 60 with its considerable extensions, a language that 
had a very strong relation to the (B) Large Systems hardware.)  
The COBOL language difficulties were subsequently fixed 
(STRING and UNSTRING, e.g. among other things) but the bad 
organization and bad coding made it terrible to use; it was 
as slow as maple syrup in Igloovik, produced inscrutable 
error messages and results that I couldn't account for.
The print-out of the compiler was about 60% Data Division 
and about 8 or 9 cm thick, and I had great difficulty 
following any of it to fix bits.  Other (B) compilers were 
pretty good and much much smaller on the whole.  

John.

-- 
John H. Lindsay                        jlindsay@kingston.net