18. A search system for determining whether an input string of characters matches a regular expression comprising a number of sub-expressions, the search system comprising: a result pipeline extending through the search system; a deterministic finite automaton (DFA) engine to store first sub-expressions that comprise strings, the DFA engine having an input to receive the input string of characters from a data pipeline, and having an output to provide a first token onto the result pipeline in response to a match with one of the first sub-expressions; a non-deterministic finite automaton (NFA) engine to store second sub-expressions having selected quantified character classes, the NFA engine having an input to selectively receive the input string of characters from the data pipeline, and having an output to provide a second token onto the result pipeline in response to a match with one of the second sub-expressions; and a token stitcher, having an input to receive the tokens from the result pipeline, to combine the tokens to generate a latch signal indicating whether the input string of characters matches the regular expression, wherein the regular expression comprises an unbounded sub-expression, and the unbounded sub-expression is delegated to the token stitcher for processing without utilizing resources of the DFA or NFA engine and wherein the DFA and NFA engines and the token stitcher are implemented by at least one processor-based computing device.
18. A search system for determining whether an input string of characters matches a regular expression comprising a number of sub-expressions, the search system comprising: a result pipeline extending through the search system; a deterministic finite automaton (DFA) engine to store first sub-expressions that comprise strings, the DFA engine having an input to receive the input string of characters from a data pipeline, and having an output to provide a first token onto the result pipeline in response to a match with one of the first sub-expressions; a non-deterministic finite automaton (NFA) engine to store second sub-expressions having selected quantified character classes, the NFA engine having an input to selectively receive the input string of characters from the data pipeline, and having an output to provide a second token onto the result pipeline in response to a match with one of the second sub-expressions; and a token stitcher, having an input to receive the tokens from the result pipeline, to combine the tokens to generate a latch signal indicating whether the input string of characters matches the regular expression, wherein the regular expression comprises an unbounded sub-expression, and the unbounded sub-expression is delegated to the token stitcher for processing without utilizing resources of the DFA or NFA engine and wherein the DFA and NFA engines and the token stitcher are implemented by at least one processor-based computing device. 25. The search system of claim 18 , wherein the DFA engine is configured to provide a trigger signal onto the result pipeline if the first sub-expression is matched by the input string of characters and the regular expression also includes one of the second sub-expressions stored in the NFA engine.