1. 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 number of pipelined search engines, each having an input to selectively receive the input string of characters from a data pipeline, and each to selectively output one of a number of tokens onto the result pipeline in response to a match between the input string of characters and a corresponding sub-expression, wherein each unique sub-expression is assigned to a corresponding one of the tokens; and a token stitcher, having an input to receive the tokens from the result pipeline, to combine the tokens to generate an output match 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 sources of the pipelined search engines and wherein the pipelined search engines and the token stitcher are implemented by at least one processor-based computing device.