There are two generic toggling commands, `(backspace)' and `(c-a)(c-(backspace))', called the "toggle" and the "long toggle".
The long toggle is meant to connote a greater dissimilarity between the related values.

When one of these toggle commands is given, a list of ML functions is successively called until one succeeds; it's a no-op if they all fail. The arguments passed are the term, and perhaps the left/right bit, and an indication of which of the two toggle commands was used.

The command `(c-a)(c-?)' will indicate whether a toggle command will have an effect on the point.

To see the descriptions of the toggle routines, click HERE. IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html