On 2020-09-02 20:15 -0400, John Cowan wrote:
> So the safe implementation is to unpack all the elements of all the ranges
> into a single vector-style range, which makes string-append O(n) but
> preserves the guarantee of an O(1) range-ref in all cases.

ACK.  I'll update the sample implementation of range-append shortly.

> I added a note that the SRFI recommends that all indexers are O(1).

This means that range-reverse should also return a vector-style range.
Since the earliest days of SRFI 196, the sample implementation of this
function has used a composed indexer (which was the only option,
pre-vector-range).

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

"The intellectual advancement of man depends on how often he can
exchange an old superstition for a new truth." --Robert G. Ingersoll