undo (was Re: Why does Dynamic Typing really matter?!?)

[Edward K. Ream]

>    Does Leo support "scoped undo" where you select a subset of the
document
> and ask for changes to be undone only for that code?

No.  There seems to be no end to the number of improvements that can be made
to editors :-)

Actually, Leo might make this possible.  The text is naturally divided into
trees and subtrees, so specifying a subtree in which to do the undo would be
easy.  Alas, undoable operations can also change the tree structure.  The
problem is less of implementation details than in trying to figure out how
to make a limited undo well defined.

In any event, all undo "beads" specify a "vnode" (part of the tree) on which
the operation is done...

Edward
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Edward K. Ream   email:  edream at tds.net
Leo: Literate Editor with Outlines
Leo: http://personalpages.tds.net/~edream/front.html
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