in RE#, we solve this by encoding the context information in the state itself. below, you can see the state machine for the regex ab(?=cd), which matches an ‘ab’ only if it’s followed by a ‘cd’. encoded in the final state, is the information that the match actually happened two characters ago.
encodes one pattern. The figure below shows an example for the seven
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"John works for Apple Inc. and lives in San Francisco.",