Re: Bidirectional text and URLs

[Eli Zaretskii]

> Date: Tue, 02 Dec 2014 09:44:17 -0500
> From: Richard Stallman <address@hidden>
> CC: address@hidden, address@hidden
> 
>   > The first one sounds pretty complicated.  I need to think about its
>   > feasibility.  It could require analysis of a very large chunk of
>   > buffer text, at least in theory.
> 
> Doesn't each paragraph do bidi separately?

Yes.

> If so, at most this requires analyzing one paragraph before and
> after the region.

That's correct, but a paragraph can be very long in some specialized
cases.  E.g., log files written by software frequently have very long
paragraphs.

>                                     What's more, the UBA specifies how
>   > to reorder text given the contents, but not how to do the reverse.
> 
> How does this relate to what I proposed?  I don't see it so I suspect
> a misunderstanding.

One way of looking at your request is to think of it as an interface
that takes reordered text in the visual order and reconstructs the
bidi context that leads to it.  The way the UBA is described doesn't
lend itself easily to such a reconstruction.

>   > Anyway, what's more important: you can have 2 without 1.
> 
> I don't understand what that would mean.

It means we can display the copied text in the same visual order
without analyzing the context that caused that visual order.

> The facility you propose here might be useful too, for other purposes.

It is already being used (I needed in the Emacs test suite to visually
compare the results of reordering with the reference implementation).