The BASIS Mechanism

The BASIS mechanism provides support to allow an entire COBOL source file to be non-interactively edited, temporarily, and the result of this edit to be submitted to your COBOL system. The COBOL source file referenced as the source of the temporary edit (the "subject program") remains unchanged, and there is no record of the result of the edit other than the files output by your COBOL system (listing, and so on). The resulting code file cannot be animated since there is no source file for reference.

The BASIS mechanism is valid for fixed-format source only.

The program submitted to your COBOL system consists of two files: an edit control file (containing the BASIS statement and editing information) and the COBOL source file (the subject program as described above).

Three special statements are associated with the BASIS mechanism:

BASIS
INSERT
DELETE.

These special statements are not part of the COBOL language. Each one must, in its entirety, be contained on a single line and must be in upper case.

If you use INSERT or DELETE statements to modify a COBOL source program specified in a BASIS statement, the sequence field of the COBOL source program must contain numeric sequence numbers in ascending order.

General Rules

To use the BASIS mechanism, you must specify the BASIS preprocessor directive: PREPROCESS(BASIS) or P(BASIS).
A DELETE statement wholly within area B of the source-program line, not followed by a valid subject-sequence or subject-sequence-range, is treated as a COBOL DELETE statement by your COBOL system.
Within the BASIS mechanism DELETE statement, all subject-sequence and subject-sequence-range numbers must be in ascending numeric order.
Within the edit control file, all subject-sequence and subject-sequence-range numbers must be in ascending numeric order.