Am So., 16. Aug. 2020 um 06:54 Uhr schrieb Arthur A. Gleckler
<xxxxxx@speechcode.com>:

>> In addition, this SRFI recommends that (where feasible) procedures that expect pairs as arguments also accept ipairs.  If such a call returns newly allocated pairs, they will be ordinary pairs; if it returns existing pairs, they will be pairs or ipairs as the case may be.

Please add the reverse as well:

In addition, this SRFI recommends that (where feasible) procedures
that expect ipairs as arguments also accept pairs.  If such a call
returns newly allocated pairs, they will be immutable pairs; if it
returns existing pairs, they will be pairs or ipairs as the case may
be.

[An example of this procedure is "icar".]