COBOL (Common Business-Oriented Language) is a compiled English-like computer programming language designed for business use. It is an imperative, procedural language that was designed in 1959.
COBOL Anti-Patterns Overview
COBOL, despite its longevity and importance in business applications, has several common anti-patterns that can lead to maintainability problems and bugs. Here are the most important anti-patterns to avoid when writing COBOL code.
Using GO TO Excessively
Avoid excessive use of GO TO
statements, which create spaghetti code that is difficult to understand and maintain. Use structured programming constructs like PERFORM
, IF-ELSE
, and EVALUATE
instead.
Using Magic Numbers
Avoid using magic numbers (hardcoded numeric literals) in your code. Use named constants to make your code more readable and maintainable.
Not Using Structured Data
Use hierarchical data structures to organize related data fields. This makes your code more readable and easier to maintain, especially when passing data between program modules.
Hardcoding File Names
Avoid hardcoding file paths and names in your programs. Use configuration files or environment variables instead, which makes your code more flexible and portable across different environments.
Not Validating Input Data
Always validate input data before processing it. This helps prevent runtime errors, data corruption, and potential security issues.
Using PERFORM THRU
Avoid using PERFORM THRU
statements, which can lead to maintenance issues if paragraphs are reordered or renamed. Use structured PERFORM
statements with well-defined paragraph boundaries instead.
Not Using COPY Books
Use COPY books to share common data definitions and code across multiple programs. This reduces duplication and ensures consistency.
Not Using Meaningful Variable Names
Use meaningful and descriptive names for variables, paragraphs, and sections. This makes your code more readable and easier to understand and maintain.
Not Using Proper Error Handling
Implement proper error handling with detailed error messages, logging, and recovery procedures. This helps diagnose and resolve issues more quickly.
Using REDEFINES Inappropriately
Avoid using REDEFINES
to repurpose the same memory location for different data types. This can lead to data corruption and maintenance issues. Use separate fields for different purposes instead.
Not Using Structured Programming
Use structured programming principles with modular design. Break down your program into logical, self-contained modules with clear responsibilities.
Not Using EVALUATE for Complex Conditions
Use the EVALUATE
statement for complex conditional logic instead of deeply nested IF
statements. This makes your code more readable and easier to maintain.