On 4 Dec 2023, at 11:54, Marc Nieper-Wißkirchen <xxxxxx@gmail.com> wrote:

> Before you write a sample implementation, please explain why you want to deviate from R6RS in the first place.

You argued previously that totally forbidding re-entry into a procedure before its final definition has been evaluated would be a wart. I agree.

> Besides, I do find this part of the SRFI 245 far less compelling than the original R6RS semantics (it is not very natural to group expressions with a definition that probably has nothing to do with the expressions).

This is an implementation detail in practice, of course. I find the insertion of ‘dummy’ variables and a ‘side-effect-free expression returning an unspecified value’ at least as unnatural. But in both cases these details are just operational definitions of what the expander internally does.

Daphne