[Axiom-math] Re: [fricas-devel] Re: [open-axiom-devel] [fricas-devel] Re: [fricas-devel] Re: [fricas-devel] Re: iterators and cartesian product.

[Gabriel Dos Reis]

On Tue, 23 Oct 2007, Bill Page wrote:

| 
| On 10/23/07, Ralf Hemmecke wrote:
| >
| > On 10/24/2007 03:07 AM, Bill Page wrote:
| > > On 10/23/07, Ralf Hemmecke wrote:
| > >>>> Seems OK, but, of course the _domain_ 1..9 is then inappropriate in a
| > >>>> construction like
| > >>>>
| > >>>>    for i in 1..9 repeat ...
| > >>>>
| > >>>> don't you agree?
| > >>>>
| > >>> No. My proposal also includes the idea that the construct
| > >>>
| > >>>     for i in X repeat
| > >>>
| > >>> should expect X to be any domain that supplies a generator (like Aldor).
| > >> In Aldor, at the place of X there must be an element of type
| > >> "Generator(Something)", not a domain.
| > >
| > > Can you give an example of an "element of type Generator(Something)"
| > > that is not a domain?
| >
| > g: Generator(Integer) := generate {yield 0}
| >
| > Take g.
| >
| 
| Ok, yes I see what you mean. But this requires some new basic
| functionality in the language, right?

I find  semi co-coroutines a possibility for Spad.

| Contrast this with 'Stream' in
| Axiom which (so far as I understand) does not require such an
| extension of Spad.

Stream is an *example* of a generator like domain.  I would not want
to turn my BinaryTree into a Stream before iterating over it.

-- Gaby