Re: The making of compilers

[byhoe@greenlime.com (Adrian Hoe)]

dewar@gnat.com (Robert Dewar) wrote in message news:<5ee5b646.0202250655.6fd2bfb8@posting.google.com>...
> "tony gair" <tonygair@nespamtome.btinternet.com> wrote in message news:<a5btuv$f62$1@knossos.btinternet.com>...
> > After sticking my neck out and being shot out out of the sky by the big
> > guns.....................................
> > 
> > I heard from a lecturer in 1990 that compilers were built 
> > by writing a language subset compiler in assembler (or C 
> > or C++ or.....) and then by using that subset to step by 
> > step extend the language to its desired form.
> 
> Yes, that's indeed the most reasonable approach if there are no
> existing compilers for the language. For example, Alsys Ada was
> initially implemented using a subset compiler written in PL/1.
> 
> By the time GNAT was being created, the Alsys compiler
> already existed, and we first wrote in Ada 83, and bootstrapped using
> the Alsys compiler on a Sun, then once
> we were bootstrapped, we step by step extended, so that
> now we use quite a lot of Ada 95 features.
> 
> > And he was really clever he was , he had glasses and a 
> > beard and everything.
> 
> I am not sure of the reason for this frivolous comment,
> but he was giving a perfectly reasonable account of how
> things are done. Your tone seems to indicate skepticism,
> but in this case I am afraid the skepticism comes from
> ignorance, and glasses-and-beard knew what he was talking
> about :-)

Interesting! One can find a lot of Ada resources on the net. History,
codes, compilers, etc. Why there isn't any Ada compilers' histories?
This could be very interesting topic to add to the Ada resources.

                              -- Adrian Hoe
                              -- http://greenlime.com/users/adrian.hoe