4. The system of claim 1 further comprising a hash map configured to store hash values of the set of tokens from the dictionary data store, wherein: the chart parser is configured to calculate a hash value of a candidate token from the input text string; and presence of the calculated hash value in the hash map indicates that the candidate token matches one of the set of tokens.
4. The system of claim 1 further comprising a hash map configured to store hash values of the set of tokens from the dictionary data store, wherein: the chart parser is configured to calculate a hash value of a candidate token from the input text string; and presence of the calculated hash value in the hash map indicates that the candidate token matches one of the set of tokens. 5. The system of claim 4 wherein the set of tokens is a proper subset of the plurality of tokens in the dictionary data store, and wherein the set of tokens is selected from the plurality of tokens based on a domain of the input text string.