Re: [PATCH] Elpa: Pinpoint semantics of `seq-subseq' for streams

[Michael Heerdegen <michael_heerdegen@web.de>]

John Wiegley <jwiegley@gmail.com> writes:

> You could implement tail as a stream adapter that basically implements a
> sliding window:
>
> Whenever an element is requested from the tail stream, it keeps
> requesting elements from the parent stream, filling up its window
> buffer and cycling out old elements, until it reaches the end of the
> parent stream.  At that point, it knows enough to start draining the
> window buffer to the caller.

Yeah, implementing it that way would be cool: if we use `stream-pop', we
would not even need to create a new stream, we would just return the
original stream `stream-pop'ped accordingly until we have found its end
- and everything wrapped inside `stream-delay' so that this is done not
before elements are requested from the returned stream.


Thanks,

Michael.