ELisp futures and continuations/coroutines (was: more url-utils?)

[Ted Zlatanov]

On Wed, 18 May 2011 19:05:57 -0300 Stefan Monnier <address@hidden> wrote: 

SM> That's a good idea.  Kind of like a future.

Speaking of futures, can we have a general facility for those?

1) a real "future" type

2) a way to construct it and check if the value is available

3) process sentinel tie-in

I'm sure much of this facility is either possible or already available
in ELisp, I just don't know the pieces and I think it would be very
convenient to provide a "future" type.  WDYT?

Similarly it would be very nice to provide continuations and coroutines
if those are not already possible.  They don't need a top-level type
though, a lexical closure is sufficient I think.  Please tell me how I'm
wrong :)

Ted