Re: overlays vs text properties

[Eric Abrahamsen]

On Wed, Jul 13 2011, Eli Zaretskii wrote:

>> From: Eric Abrahamsen <eric@ericabrahamsen.net>
>> Cc: help-gnu-emacs@gnu.org
>> Date: Wed, 13 Jul 2011 00:23:23 -0700
>> 
>> 1. I'll have a buffer and an indirect buffer on the same file. Each
>>    buffer will have a single "active" paragraph at any one time, but
>>    only one. So I don't think scaling is too much of an issue. I'm
>>    trying to create a "follow" situation, where a paragraph in the
>>    source buffer is matched to a paragraph in the indirect buffer, and
>>    these two paragraphs have (different) properties. But only the two
>>    paragraphs at one time, moving in unison.
>> 2. This is mostly a visual effect (hence my leaning towards overlays),
>>    and copying text properties is not necessary. In fact, it would be
>>    annoying.
>> 3. Overlapping would not be an issue -- within the "active" paragraphs
>>    there might be other properties present, but they would be separate
>>    from the overall paragraph property.
>> 
>> I am trying to create a translation environment, by modifying an org-mode
>> file so that I can move through one subtree while the indirect buffer
>> displays mirror paragraphs in another subtree. I want to link
>> source-language paragraphs with target-language paragraphs, so it's
>> pretty crucial that movement be covered: wherever point goes in the main
>> buffer, it should be tracked and mirrored in the indirect buffer.
>
> Sounds like overlays are better suited for this job, unless I'm
> missing something.

Only that there's no good way of moving overlays based on the movement
of point!