general undo methods?
ambassador at fourthworld.com
Sat Feb 19 13:57:57 EST 2005
Geoff Canyon wrote:
> I would store a list of transcript statements designed to undo/redo the
> things you are doing. So if you move a rectangle to 100,300 I would get
> the long id of the rectangle and do something like this:
> put "set the loc of" && it && "to" && tNewLoc & cr after gRedoString
> put "set the loc of" && it && "to" && the loc of it & cr before gUndoString
> set the loc of it to tNewLoc
> I did something like this for fields and found it to be remarkably fast
> and efficient. The really great aspect is that you can undo/redo an
> arbitrary number of steps with one command: do line 1 to 100 of
> gUndoString undoes 100 steps, etc.
That's prettyt much where I'm headed now, but there's one aspect that's
still problematic: Rev's built-in undo for text editing operations is
something I don't want to replicate. For a single-level Undo it's easy
enough to put a flag in the undo string to tell it to use the built-in
undo command rather than any custom routine. But how would one handle
this for multi-level undo?
Fourth World Media Corporation
Ambassador at FourthWorld.com http://www.FourthWorld.com
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