Abstract: A method and system for graphically generating user-defined rules to be used for checking the quality of a language. A Graphical User Interface (GUI) with a plurality of menus provides easy and effective means for generating user-defined rules. Generally, each rule comprises a node type associated with a matching function. Nodes and their properties are graphically generated and connected to construct rules. In one embodiment, the present invention graphically generates user-defined rules to be used for checking the quality of a computer programming language. Each instruction in a computer programming language is represented by at least one node of a particular type stored in a parse tree for describing dependencies between such nodes. Both the parse tree and the rules are stored in the computer. The parse tree is searched beginning from a root node indicating an entry point into the parse tree for at least one of the nodes having such a particular type matching one of the node types.