On 2020-08-30 22:43 +0200, Marc Nieper-Wißkirchen wrote:
> Am So., 30. Aug. 2020 um 22:40 Uhr schrieb Wolfgang Corcoran-Mathe
> <xxxxxx@sigwinch.xyz>:
>
> > Agreed.  The second, delayde version could be especially bad if PROC
> > is expensive.
>
> Or good because of the O(n) behavior of the first version. But that's
> just an observation and doesn't invalidate the argument.

So what's it to be?  It seems to be a trade-off.  Both approaches have
their uses, though it's not Scheme tradition to provide two versions of
the same procedure with different evaluation strategies.

(Another approach, evaluating (proc (range-ref r i)) lazily, isn't
possible with strict ranges, although it suggests further research.)

--
Wolfgang Corcoran-Mathe  <xxxxxx@sigwinch.xyz>

"The art of doing mathematics consists in finding that special case
which contains all the germs of generality." --David Hilbert