1. A method for matching regular expressions including word boundary symbols, the method comprising: receiving an input string; receiving a regular expression including a word or non-word boundary symbol; transforming, by a processor, the regular expression into an automaton such that a set of strings accepted by the automaton is the same as a set of strings described by the regular expression, wherein the automaton is a final automaton derived from a plurality of intermediate automata, and wherein transforming the regular expression into the final automaton further includes transforming the regular expression into a first intermediate automaton that accepts a string over an extended alphabet including word and non-word boundary symbols; and processing the input string by the automaton to determine if the input string matches the regular expression.