[climacs-devel] overwrite mode

[Robert Strandh]

Aleksandar Bakic writes:
 > > I would put it in base.lisp and make it a combination of (setf
 > > buffer-object) and forward-mark. 
 > 
 > I suppose you meant that the point should be moved one place to the right. How
 > would (setf buffer-object) relate to undo, for example? 

I don't know.  I guess a compound undo record could be used.  The
reason I am suggesting a combination of (setf buffer-object) and
forward-mark, is that it is potentially more efficient.

On the other hand, the real question is about semantics.  If you have
the text:

    abcdef

with the point between the c and the d, and a right-sticky mark at the
same place, then using a combination between delete and insert to
overwrite the d will put the mark between the d and the e, whereas
using a combination of (setf buffer-object) and forward-mark will
leave it between the c and the d.  The analogous thing happens to a
left-sticky mark initially between the d and the e. 

 > (Have you intentionally
 > omitted this from the buffer protocol for some reason?) 

This?  Overwrite?  No, I just don't ever use it myself.  

 > Should there also be a
 > primitive for overwriting a sequence? I don't think I ever used something like
 > that, though, but one might want to yank a sequence in the overwrite mode.

Sure, someone that uses overwrite mode might want to do that. 
-- 
Robert Strandh

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