Re: ada -> C translator

[fjh@murlibobo.cs.mu.OZ.AU (Fergus Henderson)]

dewar@merv.cs.nyu.edu (Robert Dewar) writes:

>You may remain unconvinced, but it just goes to show that you have not
>really looked at the detailed issues of implementing Ada this way.

Well, I do remain unconvinced.  In fact, so far with each detailed
issue that you have raised, the more unconvinced I have become, because
the issues you have raised are either issues that the Mercury implementation
deals with or issues which seem easily solvable.

>Also, it becomes clear that what you have in mind for an Ada compiler
>written this way is more of a small subset Ada toy than a real compiler

What I had in mind was not a small subset Ada toy; I had in mind
something that could be validated.

(Some Ada features might require small amounts of non-portable code,
but porting would still be a lot easier than porting a native-code
compiler.)

>(it is out of the question for example, for a real Ada compiler, which
>must implement pragma Import and pragma Export properly to consider not
>using an invocation stack).

I don't know what you're trying to say here.  I think this statement is
at best vacuous, and at worst false.  Certainly any implementation of a
language that supports recursion is going to need an invocation stack.
But an Ada implementation could use a different invocation stack than
the languages that it interfaces with via pragma Import and pragma
Export, and an Ada compiler that worked via compilation to C need not
use the C stack as its invocation stack.   Why do you suggest that this
would be "out of the question"?  (In case you were wondering, the
Mercury implementation has a C interface which supports functionality
quite similar to Ada's "pragma import" and "pragma export", and it does
not use the C stack as its invocation stack.)

What do you mean by a "real" Ada compiler?

--
Fergus Henderson <fjh@cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
PGP: finger fjh@128.250.37.3         |     -- the last words of T. S. Garp.