4. The method of claim 3 , further comprising: determining whether each of the transformed matches partially match the same tree pattern; if not, then determining that no candidate match can be derived; and if so, then determining whether the same candidate match is returned by multiple OP node children.
4. The method of claim 3 , further comprising: determining whether each of the transformed matches partially match the same tree pattern; if not, then determining that no candidate match can be derived; and if so, then determining whether the same candidate match is returned by multiple OP node children. 5. The method of claim 4 , further comprising: if the same candidate match is not returned by multiple OP node children, then determining that no unique matching is possible and that no candidate match can be derived; and if the same candidate match is returned by multiple OP node children, then assembling a result by concatenating candidate matches for each of the OP node children.