11. A non-transitory computer readable storage medium containing instructions that cause a data processing system to execute a method when read by said data processing system, said method comprising defining a plurality of ALTERNATIVE statements, each ALTERNATIVE statement of said plurality of ALTERNATIVE statements comprising: a label that identifies said ALTERNATIVE statement; a signature that defines a test that is to be performed on a first field in said record; and a NEXT statement that identifies a different one of said ALTERNATIVE statements and that defines a second field in said data record to be said first field in said different one of said ALTERNATIVE statements if said test is satisfied, said data processing system generating an error if said test is not satisfied, wherein said first and second fields are different in at least one of said ALTERNATIVE statements and wherein said NEXT statement in one of said ALTERNATIVE statements specifies a plurality of fields for testing in a predetermined sequence by other ALTERNATIVE statements in a processing program, control being transferred to the first one of said other ALTERNATIVE statements in said predetermined sequence in which said test in that one of said other ALTERNATIVE statements is satisfied.
11. A non-transitory computer readable storage medium containing instructions that cause a data processing system to execute a method when read by said data processing system, said method comprising defining a plurality of ALTERNATIVE statements, each ALTERNATIVE statement of said plurality of ALTERNATIVE statements comprising: a label that identifies said ALTERNATIVE statement; a signature that defines a test that is to be performed on a first field in said record; and a NEXT statement that identifies a different one of said ALTERNATIVE statements and that defines a second field in said data record to be said first field in said different one of said ALTERNATIVE statements if said test is satisfied, said data processing system generating an error if said test is not satisfied, wherein said first and second fields are different in at least one of said ALTERNATIVE statements and wherein said NEXT statement in one of said ALTERNATIVE statements specifies a plurality of fields for testing in a predetermined sequence by other ALTERNATIVE statements in a processing program, control being transferred to the first one of said other ALTERNATIVE statements in said predetermined sequence in which said test in that one of said other ALTERNATIVE statements is satisfied. 12. The non-transitory computer readable storage medium of claim 11 wherein one of said NEXT statements includes a first ALTERNATIVE statement, a backtrack operator, and a second ALTERNATIVE statement, control being transferred to said second ALTERNATIVE statement when a sequence of ALTERNATIVE statements beginning with said first ALTERNATIVE statement generates said error.