[climacs-devel] a paragraph on persistent buffers

[Aleksandar Bakic]

>  > > An undo record of a regular buffer only keeps an editing
>  > > operation, I think.
>  > 
>  > I can´t access the code at the moment, but I guess a regular undo record
> also
>  > keeps a pointer to the buffer (as opposed to the contents of it (a tree)
> kept
>  > by a persistent undo record), so the difference is an edit operation (at
>  > least).
> 
> Not sure what you mean, but if memory serves, an undo record contains
> buffer offsets as opposed to (say) marks, since we rely on undo
> operations to be applied in the reverse order compared to ordinary
> operations. 

Sorry, I am forgetting the terminology. I meant the same by the "editing
operation": offsets plus the kind of operation and perhaps a text operand. The
operation gets reversed once it is undone so that it can be redone. No such
thing in a persistent buffer's undo record. (Also, just to repeat: with both
kinds of buffers, markers are generally invalidated by undo/redo, even though
they remain valid for some undo/redo operations with standard buffers.)

Alex


		
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