At 12:55 PM -0800 on 11/20/99, Alain Farmer wrote:
>Alain: It depends on the action taken, doesn't it?
>From a user's perspective, the "undo" menuItem is
>sometimes disabled (e.g. cannot undo certain actions).
>For the irreversible actions to be made reversible,
>the system will have to keep intermediate versions
>(one for each irreversible action). Please tell me
>that I am wrong.
You're wrong :) Only enough information has to be kept to undo the action.
Example:
Action=Create button
Undo=Delete button
Action=Delete button
Undo=Create button with properties so-and-so, script so-and-so,
contents so-and-so.
And so on.
>
>Uli: And since memmap isn't available on Macs, we
>can't use libundo anyway.
>
>Alain: Is there some fundamental reason why the Mac
>does NOT do memmap?
Yes -- Apple's VM system sucks. Consider to add one MB of VM to my 104MB
Mac takes 105MB of disk space. On any other system, 105MB of disk spaces
adds 105MB of RAM -- as it should.
