GNU bug report logs - #23102
Wrong usage of underscore in .tex files

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Message #14 received at 23102 <at> debbugs.gnu.org (full text, mbox):

From: Tassilo Horn <tsdh <at> gnu.org>
To: Angelo Graziosi <angelo.graziosi <at> alice.it>
Cc: John Wiegley <jwiegley <at> gmail.com>, 23102 <at> debbugs.gnu.org
Subject: Re: bug#23102: Wrong usage of underscore in .tex files
Date: Mon, 28 Mar 2016 11:46:18 +0200

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

Angelo Graziosi <angelo.graziosi <at> alice.it> writes:

Hi Angelo and John,

>>> Attached is how Emacs displays the usage of underscore out of
>>> mathematics and friends, for example:
>>
>>> \href{http://www.foo.it/bla_bla.html}{BLA_BLA}
>>
>> I'm pretty sure that the underscore in BLA_BLA here is incorrect LaTeX.
>> Shouldn't it be BLA\_BLA, which does display correct in latex-mode?

Well, the plain underscore in BLA_BLA is indeed wrong but the plain
underscore in the URL *is* correct though escaping it with \ is also
permitted.

> Yes, it works but it is only a workaround in my opinion: treating an
> url string as in mathematics seems wrong to me.
>
> I found no example suggesting to use \_ in \href{}{} or \url{} commands.

Right, you don't need to use \_ in \url{} or \href's 1st argument.
Interestingly, stock `latex-mode' displays the argument of \url{} as
verbatim without subscripting the character after the _.  It should do
the same with the first argument of \href.

> I tried with Atom Editor and its language-latex package, and the above example
> (BLA_BLA...) is displayed as expected from me. See attachment.

GNU AUCTeX does the same: _ has only subscript semantics in math mode.

[Screenshot from 2016-03-28 11-35-18.png (image/png, attachment)]

[Message part 3 (text/plain, inline)]

Bye,
Tassilo

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