Re: Should invisible imply intangible?

[David Kastrup]

Richard Stallman <address@hidden> writes:

>     Well, I already explained that in the case of an overlay, the display
>     property is not really connected with the text but with the buffer
>     locations.
> 
> You've stated your views, but I don't agree.

In the case you should put forward a proposal that matches your views
consistently.  In particular, how would your model treat an overlay
having a display property with an image in it, when the text up to and
including character 10 of the buffer was invisible (due to a text
property, for example), and both overlay-start and overlay-end are 11.
This is an empty overlay, not convering any character, and the
character left from it is invisible, the character right from it is
visible.  According to your opinion, the visibility of the overlay
should be connected with the text it covers, but it does not cover
any.

So how would you want to treat this case?  There is a price I will
have to pay for an implementation of your views: it will be rather
hard to come up with working code for the preview-latex package for
both Emacs-21.3 and Emacs-21.1, and people upgrading their Emacs while
keeping a now current version of preview-latex will have it break.  I
would be loath to pay this price for the mere replacement of one
inconsistent interface with another.

So please let us get a complete scheme worked out of how to deal with
all cases involved before implementing things, and save the actual
interface change for 21.3, letting 21.2 still work in the old way.

Thanks,

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum
Email: address@hidden