>nil   - Trivially defined (define nil '()), for SICP exclusively use it as an empty list.

Excellent catch! I didn't notice it.

>but the implementation isn't shown in the book, I think.

The implementation is shown for the ordinary (put) and (get).
My view on this is that this SRFI should provide only the features
that are not explicitly described in the book, while the
implementation of (put-coercion) is a few sexps away from (put).

On Thu, 5 Nov 2020 at 19:12, Shiro Kawai <xxxxxx@gmail.com> wrote:
>
> I have a small file to try SICP on Gauche.   Here are other nonstandard stuff:
>
> nil   - Trivially defined (define nil '()), for SICP exclusively use it as an empty list.
>
> put-coercion, get-coercion  (2.5.2) - it is trivial to implement it using tables, but the
> implementation isn't shown in the book, I think.
>
>

--
Yours sincerely, Vladimir Nikishkin
(Sent from GMail web interface.)