1 to say that you did not mean something you said earlier or say that you have changed your opinion: --
She refused to backtrack from her criticisms of the proposal.
The officers were forced to backtrack on their statements.
[ + speech ] "All right," he backtracked, "It's possible that I was mistaken."
2 to go back the same way you came, or to consider information again: --
In this case backtracking must take place to the most recent choice point either in clause selection or in unification.
Any feature structures and definite clause programs can be used to express the constraint, which may include backtracking, cut, negation-as-failure, assertion and any other operations.
If a sub-string matches the contextual restrictions, the corresponding operation applies without later backtracking.
Upon backtracking the registers that held these system variables are restored from the choicepoint.
The other kind of error - incompleteness via infinite loops or backtracking failure - continues to be bothersome, of course: dependent types do not save us there.
By contrast, backtracking automata cannot be easily analyzed.
14 again because backtracking does not remove the reason for the failure !.
Profiling revealed that in this benchmark, upon backtracking and untrailing it is often needed to remove several cells at once from a certain remembered set.
