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Re: [Axiom-developer] Spad and its object model
From: |
Gabriel Dos Reis |
Subject: |
Re: [Axiom-developer] Spad and its object model |
Date: |
Mon, 11 Jun 2007 16:26:48 -0500 (CDT) |
On Mon, 11 Jun 2007, Waldek Hebisch wrote:
| Gaby, did you look how Axiom uses arrays of function pointers?
Yes. :-)
| At
| the first glance they are like vtables. But there is a fundamental
| difference: Spad domain uses only its own domain vector -- it never
| directly uses ancestor vector.
^^^^^^^^
What do yo mean by "never directly"?
check out lookupCompete and lookupIncomplete.
[...]
| There are issues with coherence, but IMHO they are unavoidable
| given static typechecking and dynamic runtime: Spand compiler
| checks that intefaces to domians are compatible at compile
| time, but you may redefine things in incompatible way and
| recompile only some objects later.
Why do you believe this is unavoidable?
| Say you compile D which
| references Integer. Later you redefine Integer in incompatible
| way and recompile Integer (but keep ald object for D).
The system should be able to catch that, precisely.
| D
| references Integer by name and in fresh inage will pick
| new definition of Integer, giving runtime problems.
this is one root of the problem. Another root is the way lookup
functions work.
[...]
| AFAICS problems of "post facto extensions" have nothing to do
| with usage of arrays to cache lookups. IMHO main problem is
| that Axiom has just one "handle" to access given domain.
| Namely domain Integer defines function also named Integer
| which build domain vector.
I don't think, that is the main problem.
-- Gaby
- Re: [Axiom-developer] Spad and its object model, (continued)
- Re: [Axiom-developer] Spad and its object model, Stephen Wilson, 2007/06/11
- Re: [Axiom-developer] Spad and its object model, Gabriel Dos Reis, 2007/06/11
- Re: [Axiom-developer] Spad and its object model, Stephen Wilson, 2007/06/11
- Re: [Axiom-developer] Spad and its object model, Gabriel Dos Reis, 2007/06/11
- Re: [Axiom-developer] Spad and its object model, Stephen Wilson, 2007/06/11
- Re: [Axiom-developer] Spad and its object model, Gabriel Dos Reis, 2007/06/12
- Re: [Axiom-developer] Spad and its object model, Stephen Wilson, 2007/06/12
- Re: [Axiom-developer] Spad and its object model, Gabriel Dos Reis, 2007/06/12
- Re: [Axiom-developer] Spad and its object model, Stephen Wilson, 2007/06/12
Re: [Axiom-developer] Spad and its object model, Waldek Hebisch, 2007/06/11
- Re: [Axiom-developer] Spad and its object model,
Gabriel Dos Reis <=