1. A system for the processing of the characters of an input message in accordance with pre-determined format rules, comprising: a rules execution engine having an input for receiving an input message and having an output, the rules execution engine for executing one or more processing production rules that alter the format of the input message and for providing the so-altered input message as an output thereof; and an extensible production rule set containing therein a plurality of production rules each having a criteria triggerable by more or characters of the input message to cause execution of that so-triggered rule by the rules execution engine to alter the format of the input message in accordance with an action function or the action functions of the so-triggered rule wherein each production rule includes a left-hand side having a condition or criteria that can be selectively triggered by one or more characters of the input message and a corresponding right-hand side having one or more executable format-altering action functions, a rule, when the left-hand side is fired or triggered by one or more characters of the input message, being executed by the rules execution engine to cause the corresponding execution of the action function or action functions of the right-hand side to alter the format of the message.