GNU bug report logs - #37633
Column part interpreted wrong in compilation mode

Previous Next

Full log

Message #17 received at 37633 <at> debbugs.gnu.org (full text, mbox):

From: Bernd Paysan <bernd <at> net2o.de>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 37633 <at> debbugs.gnu.org, anton <at> mips.complang.tuwien.ac.at
Subject: Re: bug#37633: Column part interpreted wrong in compilation mode
Date: Sat, 05 Oct 2019 19:05:26 +0200

[Message part 1 (text/plain, inline)]

Am Samstag, 5. Oktober 2019, 18:16:53 CEST schrieb Eli Zaretskii:
> > Date: Sat, 05 Oct 2019 19:08:21 +0300
> > From: Eli Zaretskii <eliz <at> gnu.org>
> > Cc: 37633 <at> debbugs.gnu.org, anton <at> mips.complang.tuwien.ac.at
> > 
> > > Suggested solution: Use byte-to-position to calculate the position in
> > > compilation-move-to-column.
> > 
> > This only works in UTF-8 locales, and is not 100% even there, so it
> > isn't the right solution.
> 
> In general, byte-to-position is meant to be used only for converting
> between byte and character positions of text in Emacs buffers.
> 
> For byte offsets in external text we have bufferpos-to-filepos, but
> that requires us to know the encoding of the external text.  We need
> to find a reasonable way of getting that.  Suggestions and patches
> welcome.

We can likely assume that the auto-detected encoding is the correct one, i.e. 
buffer-file-coding-system can be used (the default for the optional encoding 
system parameter for bufferpos-to-filepos and filepos-to-bufferpos).

I.e. go to the line selected, do a bufferpos-to-filepos on that position, add 
the column-1 to that, and do a filepos-to-bufferpos.  Jump there.

Problem with precision: "exact" requires encoding the entire file, so it's 
slow for large files.  Particularly with automatically generated files, this 
is likely not acceptable, so "approximate" could be good enough.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
net2o id: kQusJzA;7*?t=uy <at> X}1GWr!+0qqp_Cn176t4(dQ*
https://net2o.de/

[signature.asc (application/pgp-signature, inline)]

Previous Next

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