GNU bug report logs - #73764
format-kbd-macro returns a key name that keymap-lookup doesn't recognize

Previous Next

Full log

Message #14 received at 73764 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 73764 <at> debbugs.gnu.org, eduardoochs <at> gmail.com
Subject: Re: bug#73764: format-kbd-macro returns a key name that
 keymap-lookup doesn't recognize
Date: Sat, 12 Oct 2024 17:36:05 +0300

> From: Stefan Monnier <monnier <at> iro.umontreal.ca>
> Cc: Eduardo Ochs <eduardoochs <at> gmail.com>,  73764 <at> debbugs.gnu.org
> Date: Sat, 12 Oct 2024 09:33:59 -0400
> 
> >>   (keymap-lookup global-map "M-C-h")
> >>     ;;-> "M-C-h" is not a valid key definition; see `key-valid-p'
> [...]
> > Should we fix key-valid-p to be more lenient?
> 
> AFAIK the strictness was a conscious choice, so maybe we should simply
> improve the error message to say something like "M-C-h uses an invalid
> modifier ordering, maybe you meant C-M-h".

The general problem is much wider, so it is not easy to intuit "what
you meant".  E.g., what do you say if the key is "S-s-M-H-A-C-b"?  Do
you want to have a function that reorders the modifiers in canonical
order?  And if we have such a function, why not reorder silently and
accept the key, like we do with the order of BEG..END in functions
that accept the region?

> >> if we run this
> >>
> >>   (format-kbd-macro (read-key-sequence-vector "Type C-M-h:"))
> >>
> >> we get "M-C-h".
> 
> I guess we also need to make sure `format-kbd-macro` generates
> something that `key-valid-p` accepts.

AFAICS, that's impossible without completely rewriting its code.  It
proceeds from left to right (i.e. from MSB to LSB).

> > Or maybe just remove the call to keymap--check from keymap-lookup?
> 
> IIRC we wanted to use `keymap--check` on all input coming from the user,
> so I guess the question is whether the second arg of `keymap-lookup` is
> expected to be an immediate constant.

But keymap-look up is not an interactive function.

> That function is still young, so it's hard to tell how it'll turn up,
> but my `grep` says that indeed many (most) calls take a literal string
> as argument, so `keymap--check` seems appropriate.

If we remove the call to keymap--check, won't the other APIs signal an
error instead?  If they will, why do we need to protect them?

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.