Have you ever been panicked or exasperated by an illegible code? We offer you to get out of this anxiety-provoking cycle and thus, equipped with the right method and a good tool, to carry out the maintenance and evolution of complex codes …

In this article, I present how to write custom Cobol rules with SonarQube and some caveats I encountered. The targeted audience should have some basic compiler knowledge (AST, Lexical analysis, Syntaxic analysis).