It's not O(n). It's just O(k) where k is the number of arguments and thus O(1) in the sense of this SRFI.

John Cowan <xxxxxx@ccil.org> schrieb am Di., 1. Sep. 2020, 20:42:
Oh, of course it is.  Thanks.

I presume we can't do better than O(n) for this one, as the default worst case is to copy all the elements of all the ranges into a vector.

On Tue, Sep 1, 2020 at 2:40 PM Arthur A. Gleckler <xxxxxx@speechcode.com> wrote:
On Tue, Sep 1, 2020 at 11:23 AM John Cowan <xxxxxx@ccil.org> wrote:
I'm about to add this. but I don't understand "(let f ((i i) (ranges ranges) (lens lens))".  It does not appear to be standard Scheme. 

It looks like the beginning of a named let.