Re: Infinite lists (was Re: RFC 24 (v1) Semi-finite (lazy) lists)

[Ken Fox]

John Porter wrote:
> Jeremy Howard wrote:
> > Yes, they're not identical. What I mean of course is:
> >   (..-1) == reverse(map -__ (1..));
> 
> WHAT?  So the semantics of .. are magically different in the context
> of (..$n) so as to produce numbers in descending order?

Both of those expressions are the infinite list (-infinity..-1). I have
no idea how to write that properly 'cause I'm not a math guy. These
things aren't streams (infinite queues) -- they're infinite stacks. I'm
not sure they have a name in computer science.

Somebody proposed that we have lists that are infinite in both
directions, but I'm having trouble understanding how those would be
useful. Anybody want to take a few minutes to teach the math-impaired
among us?

- Ken