COBOL idioms and clean code

Sentences and verbs

A COBOL sentence is one or more verbs ending with a period. Keep one verb per sentence in new code: it makes the debugger and the reviewer agree on what happened:

ADD WS-HOURS TO WS-TOTAL-HOURS. MOVE WS-TOTAL-HOURS TO WS-REPORT-FIELD.

Scope terminators

Scope terminators (END-IF, END-PERFORM, END-EVALUATE) make nesting explicit. With them, a period ends only the sentence it belongs to, and nested blocks cannot swallow each other:

IF WS-OK PERFORM PROCESS-ROW END-IF.

Daily habits

Uppercase verbs and keywords, lowercase user names. Prefix working storage with WS-, keep paragraphs short, and let the compiler check every field with DATA DIVISION declarations before PROCEDURE DIVISION uses them.

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Article author: Arthur Isaev