Eric Stevens
Even with the most ancient of tools you can achieve the 'undo' or reversion effect you are talking about simply by doing your editing on a copy of the original. I was doing this with Photo Paint macros, backin the early 90's.

nospam
that does *not* give you the reversibility because it's not a non-destructive workflow.

Eric Stevens
Of course it is: I did it on a copy. Always, even now I never modify the original.

nospam
that's not what a non-destructive workflow is.

Eric Stevens
It's certainly a non-destructive workflow.

So too is making a background copy before you start anything else.

nospam
if we use your definition, then deleting a file is non-destructive because you can retrieve it from a backup.

Eric Stevens
You could stretch it that far, yes.

nospam
also with your definition, you can't go back and change the amount of an adjustment unless you saved a copy of every possible value. worse, the number of files you'd need to save goes up dramatically the more adjustments you make.

Eric Stevens
You only wanted non-destructive. Well, I can add this additional requirement with an editable macro file.

nospam
therefore, your definition is wrong.

Eric Stevens
You haven't really thought about it.