Re: Escaping a string for substitute-command-keys

["Clément Pit-Claudel" <cpitclaudel@gmail.com>]

On 2019-10-03 12:31, Eli Zaretskii wrote:
>> From: Clément Pit-Claudel <cpitclaudel@gmail.com>
>> Date: Thu, 3 Oct 2019 09:52:31 -0400
>>
>> I think I've seen a thread about this in the past, but I can't find it. What's the expected way to escape a string before its fed to substitute-command-keys, so that substitute-command-keys reconstructs the original string?
>>
>> The reason for this question is that since 2015 Emacs has been calling substitute-command-keys on help-echo messages, which breaks flycheck and flymake (a simple way to reproduce the issue is to enable flymake in a Python buffer containing just xxx and to hover over the xxx with the mouse: Emacs shows a tooltip containing "Undefined name ’xxx’").
>>
>> So, what's the right way to escape a string to be fed to substitute-command-keys?  Alternatively, is there be a way to disable the transformation for a particular help-echo string, rather than forcing an unnecessary rountrip?  Maybe we could add a text property, so that if a string is tagged with a 'text-quoting-style property that style is used instead of the default one?
> 
> If I understand what you are looking for, the answer is in the manual:
> quote any character with \= (in a Lisp string, that's "\\=", of
> course).  See the node "Keys in Documentation" in the ELisp manual.

I saw that part in the manual, but I was looking for a function that would do that.  Is there an easy way to tell what needs escaping, or should I just escape all `, ', and \? (and if so, should we add a function that does that to subr-x.el or somewhere similar?)

Clément.