[Axiom-developer] RE: XML

[Page, Bill]

On Tuesday, June 14, 2005 11:52 PM Tim Daly wrote:

> > > \spadcommand{x:=2}\bound{x}
> > > \spadcommand{y:=3}\bound{y}
> > > \spadcommand{x*y}\free{x}\free{y}
> > > 
> > > clicking on the third expression tells the browser that it needs to 
> > > find a meaning for x and a meaning for y somewhere prior in the page.
> > > these are determined by the \bound expression.
> > 
> > Can you give an example?
>
> cd mnt/linux/doc/hypertex/pages
> fgrep free *

Yes, I see it everywhere. But what does it do?

You said: "clicking on the third expression tells the browser that
it needs to find a meaning for x and a meaning for y somewhere prior
in the page."

What do you mean by "find a meaning for x"? Do you mean that when
you click on some expression (presumably intending that Axiom execute
this expression), that the browser actually builds some kind of
dependency tree and then executes (i.e. passes commands to Axiom)
the minimum number of commands needed to compute this expression?
This would be a form of lazy evaluation.

If this is the case, then Axiom's browser is doing a lot more than
just browsing. This is more or less the problem to which I was
referring when I asked in a previous email what we could do about
a set of related pages in which one page contained Axiom calculations
that depended calculations contained on one another page. In that
case I can see how this "free" and "bound" thing might be used.

Does the Axiom browser only look for bound variables occurring
earlier on the same page?

Regards,
Bill Page.