Re: Replace selective-display in Gnus

[Reiner Steib]

On Fri, Oct 16 2009, Katsumi Yamaoka wrote:

>>>>>> Katsumi Yamaoka wrote:
>> `next-single-char-property-change' used in `gnus-summary-show-thread'
>> is not available in XEmacs 21.4 and SXEmacs.  [...]
>
> Not only in XEmacs 21.4 and SXEmacs but also in XEmacs 21.5 and
> Emacs 21, `C-M-h' works but `C-M-s' doesn't.

Oh, that's bad.

>> Could it be replaced with a certain overlay function, like
>> `next-overlay-change' (that XEmacs provides for the compatibility)?
>
> After all I used the pure `extent' functions of XEmacs (not
> fsf-compat/overlay.el) to fix the functions that replace
> the selective-display feature of Gnus.
>
> NOTE:
> XEmacs 21.4 and SXEmacs users need to have the `calendar' XEmacs
> package installed, that provides the `add-to-invisibility-spec'
> function in auto-autoloads.el.

That is a strange dependency.  Why is such a (core) function defined
in the calendar package?  If we keep this dependency, please add it to
(info "(gnus)XEmacs") and add an appropriate error message at runtime.

But the whole point of these changes were to allow to declare
selective-display obsolete in the current Emacs version (Gnus is the
only use).  Adding so many compatibility hacks is ugly, IMHO.  I'd
rather keep the old selective-display code for Emacs 21 and XEmacs
(with appropriate feature tests for `remove-overlays'
`next-single-char-property-change'.  WDYT?

Bye, Reiner.
-- 
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