RE: [Axiom-developer] RE: algebra Makefiles with explicit dependencies, bootstrap, fixed-points etc.

[Bill Page]

On Saturday, January 08, 2005 6:20 PM Stephen Wilson wrote:
> ... 
> I'm thinking about two options for extending the axiom compiler.
> We could formalize a `compilation model', where given a file
> which references itself either directly or indirectly, the
> compiler updates all domains/categories implicitly as needed
> ( my intuition tells me this is dangerous. Even if the compiler
> implemented such a model perfectly, bugs could be subtle and
> hard to track down ).

I am not sure I understand what you mean by a `compilation model'
in the case of a language like Axiom. Could you suggest some
relevant references?

> A second alternative is to explicitly support mutually recursive
> structures in the language. I believe haskell and ocaml, for
> example, allow such constructions.

Right on! It seems to me that mutual recursion is exactly what
is going on here (the hard way by iteration! :) And I believe
that haskell and ocaml are excellent examples from which to draw
extension to Axiom (and Aldor).

Here are some references on mutual recursion that seem
quite relevant to me;

http://portal.acm.org/citation.cfm?id=507644

" ... We propose a practical and simple extension of the Modules
language that caters for cyclic dependencies between both types
and terms defined in separate modules...."

http://www-2.cs.cmu.edu/~rwh/courses/modules/papers/russo01/paper.pdf

http://citeseer.ist.psu.edu/context/1748065/439939

"This enables mutual and self recursive structures, commonly
occurring in object-oriented programs, to be readily specified.
In this paper, we provide a fixed point interpretation of such
definitions."

http://www.itee.uq.edu.au/~smith/papers/zb2000.pdf

Of course there are many more good papers on mutual recursion.

Regards,
Bill Page.