Backtracking

backtracking algorithm

Backtracking is used to solve problems in which a sequence of objects is chosen from a specific set so that the sequence satisfies some criterion. The classic example of the use of backtracking is the n-Queens problem.

This grammar only uses tokens and rules, so there is no backtracking involved, and the grammar is a predictive parser. This is fairly typical. Many grammars work fine without backtracking, or with backtracking in just a few places.