Re: Bidirectional text and URLs

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 01 Dec 2014 05:18:01 -0500
> From: Richard Stallman <rms@gnu.org>
> CC: larsi@gnus.org, emacs-devel@gnu.org
> 
>  > The issue here is that bidirectional display features are being
>   > (ab)used to trick humans into thinking they will follow a link to some
>   > place, while in fact the link leads to a very different place.  This
>   > problem would not have existed without humans reading the URLs, and
>   > without the discrepancy between what those humans perceive visually
>   > and the actual URL as seen by the program which interprets it.
> 
> That is true.  These magic characters have the same effect in URLs
> as everywhere else, because Emacs display does not distinguish.
> 
> But URLs are not the places where these magic characters are useful
> and meant to be used.

Not in the host.domain parts, but URLs can hold more than just that.
The query part, the one after the "?", might very well use it.

Anyway, if we want to detect the cases that are simple for detection,
we can start there; it's probably better than nothing.  But we need to
have a very specific definition of those cases.  Many people in this
thread talk in terms of vague concepts, such as "directionality",
which sound intuitive, but break down as soon as we need to translate
them into requirements for what Emacs should do.  Not their fault, of
course: the issue is complex and most people don't know the details,
or need to.  But it does make the discussion more difficult.