[Axiom-developer] Re: [fricas-devel] Re: iterators

[Martin Rubey]

Waldek Hebisch <address@hidden> writes:

> Well, concat version creates intermediate lists and concatenates them.
> Psychologically double iteration is an atomic operation, so it is
> easier (at least for some folks) to think about.

OK.  I'd still prefer to keep the language simple.  What I would like a lot
however is something like

for e in g repeat
    (a, b) := e
    ...

or even

for (a, b) in g repeat
    ...

given that g returns a Cross.

> Once you have generator iteration is easy (but may be inefficient).

There is a long thread "generators in lisp" in comp.lang.lisp 2004, but I
didn't read it yet.  Maybe that would help?

(But I hurry to stress that having generators is not the thing I need most in
SPAD.  Most important to me would still be types being truly first class
objects.)

Martin