Re: [PATCH 0/4] Fix caret errors

[Hans Åberg]

> On 22 Apr 2019, at 07:29, Akim Demaille <address@hidden> wrote:
> 
>> The only safe way is to replace the visible characters in the quoted string 
>> with spaces, and then use an initial portion of that. Then you can count 
>> characters as you like, probably tabs as 1.
> 
> What do you mean by "the only safe way"?  Paul's proposal a la diff -T,
> or GCC9's approach both seem to work properly.

In case somebody mixes tabs and spaces, like four space for tabs and mixed with 
spaces?

>> Does not work with Unicode, though. In your example
>>> input.y:15.4-17: warning: empty rule without %empty [-Wempty-rule]
>>> e: {∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}
>>>   ^~~~~~~~~~~~~~
>> here, the U+20D7 COMBINING RIGHT ARROW ABOVE for the nabla combines, but 
>> others do not.
> 
> What do you mean?  I see it perfectly: arrows are combined to E and B.
> It might be something on your mail reader side?  

Right, it depends on the renderer, so if you want a different line with 
matching spacing, that is not really possible.

> For some reason, in
> Apple's terminal, both nabla and B are correctly "accented", but not
> the E.  All are correct in the mailer though.

I use Mail on MacOS 10.13.

> It looks correct in Safari, and in Firefox (but less readable with the
> latter).
> 
> https://lists.gnu.org/archive/html/bison-patches/2019-04/msg00017.html

In Firefox, bot not Safari, here.

But there are other cases. I tried 𝛾̇ on the Unicode list, but somebody else 
saw it not combined and did not realize it to be a curve derivative.