Re: The making of compilers

[byhoe@greenlime.com (Adrian Hoe)]

dewar@gnat.com (Robert Dewar) wrote in message news:<5ee5b646.0203011135.12a13558@posting.google.com>...
> 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.
> 
> In our case, one of the really big advantages in writing
> the COBOL compiler in COBOL was speed, the Realia COBOL
> compiler is far far faster than other compilers around
> for the PC. To give an idea of the speed, on a 25MHz
> 386, the compiler (about 120K Sloc) would bootstrap in
> under two minutes. Of course on a modern fast PC, running
> perhaps 40 times faster, that should be down to well
> under 10 seconds (I have not run it recently). That kind
> of speed is welcome when developing large programs such
> as a compiler :-)
> 
> Robert Dewar


I remembered that I had worked on a COBOL project 10 years ago. I
wrote a command parser entirely in COBOL for my company project, fMRP.
This parser would parse business rules entered by its users. As I
still remembered, it contained not less than 9K SLOC.

I am not surprised that one can write a compiler using COBOL. :)

                                       -- Adrian Hoe
                                       -- http://adrianhoe.com