Am Mi., 14. Okt. 2020 um 11:11 Uhr schrieb Shiro Kawai <xxxxxx@gmail.com>:
>
> What I'm thinking is that define-auxiliary-syntax creates a binding in the srfi.207 module and then imports it to the current module (with the same mechanism as renaming import).

If Gauche allows importing modules lexically locally (e.g. in place of
other definitions at the beginning of a body) that sounds like a very
good approach. If it works out, I can mention it in the implementation
section.

> Actually, is there a case that the difference between 'defining a syntactic binding' and 'importing a binding' matter?  Internally they are different in Gauche, and there are edge cases that can reveal the difference, but as far as the code is valid in R7RS and srifs I suppose there's no difference.

In the case of SRFI 206, I don't think there is a difference. Usually,
definitions create new bindings, which imports doesn't. But SRFI 206's
define-auxiliary-syntax is more like SRFI 212's alias, which doesn't
create a binding, when the auxiliary syntax binding has already been
created somewhere else (e.g. lazily in the (srfi 206 all) module).