save : unit -> proof
STRUCTURE
SYNOPSIS
Marks the current proof state as a save point, and clears the automatic undo history.
DESCRIPTION
The function save is part of the subgoal package. A call to save clears the automatic proof history and marks the current state as a save point. A call to backup at a save point will fail. In contrast to forget_history, however, save does not clear the initial goal or any previous save points. Therefore a call to restore or restart at a save point will succeed. For a description of the subgoal package, see set_goal.
FAILURE
The function save will fail only if no goalstack is being managed.
USES
Creating save points in an interactive proof, to allow user-directed back tracking. This is in contrast to the automatic back tracking facilitated by backup.
SEEALSO
HOL  Trindemossen-1