1. A method of operating a computer system to form computer program code from source statements indicative of process control operations, the source statements including both textual statements and symbols associated with certain of such textual statements, each such symbol being selected from among a set of available symbols, each of such available symbols signifying an order for performance of the operations represented by the associated textual statements, such method comprising the steps of: operating the computer system so as, for each occurrence of one of such predetermined symbols, to identify those source statements associated therewith; and operating the computer system so as to translate the predetermined symbols into appropriate, more-detailed commands to cause the operations represented by such source statements to be performed by the computer system in the order represented by such symbols.