bug#40549: More usability issues:

[zimoun <zimon.toutoune@gmail.com>]

On Tue, 12 May 2020 at 10:51, Ludovic Courtès <ludo@gnu.org> wrote:

> Nothing new here, and everything is properly documented.

Using optional argument with short-option names is unusual, AFAIK.
And for sure, there is an ambiguity; as we are seeing here. :-)
However, the only mention of that is in the commentaries of srfi-37.

--8<---------------cut here---------------start------------->8---
;;; `required-arg?' and `optional-arg?' are mutually exclusive
;;; booleans and indicate whether an argument must be or may be
;;; provided.  Besides the obvious, this affects semantics of
;;; short-options, as short-options with a required or optional
;;; argument cannot be followed by other short options in the same
;;; program-arguments string, as they will be interpreted collectively
;;; as the option's argument.
--8<---------------cut here---------------end--------------->8---

http://git.savannah.gnu.org/cgit/guile.git/tree/module/srfi/srfi-37.scm#n51


Well, using short-option with optional-argument is not recommended by
POSIX, neither GNU (if I understand well)

https://pubs.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap12.html#tag_12_02
https://www.gnu.org/software/libc/manual/html_node/Argument-Syntax.html


Therefore, it deserves to document it, IMHO.