This class is both a factory for XPath location path expressions, which are built from the opcode map output, and an analysis engine for the location path expressions in order to provide optimization hints.
Bit is on if any of the walkers contain a following step.
Bit is on if the expression is a match pattern. If any of these bits are on, the expression may likely traverse outside the given subtree. First 8 bits are the number of top-level location steps. First 8 bits are the number of top-level location steps. Bit is on if any of the walkers contain a following step.