20. The computer-readable storage medium of claim 18 , wherein the at least one string pattern is a regular expression.
18. The computer-readable storage medium of claim 17 , wherein the computer-readable storage medium is encoded with instructions that, when executed, cause the at least one processor to: compare the plurality of respective characters associated with the plurality of respective keys to at least one string pattern that include the at least one metacharacter, wherein the at least one string pattern is associated with the category; and identify the category based on determining that the plurality of respective characters match the at least one string pattern.