NewComboGenerator returns a generator for queries produced by a combination of rules on a seed query.

NewSmartSearchJob creates generators for opportunistic search queries that apply various rules, transforming the original input plan into various queries that alter its interpretation (e.g., search literally for quotes or not, attempt to search the pattern as a regexp, and so on).

Do not run autogenerated queries if RESULT_THRESHOLD results exist on the original query.

FeelingLuckySearchJob represents a lucky search.