Inspecting and Visualizing Language Extensions in Storm : A Developer Tool for Inspecting DSL Parsing

Sammanfattning

A major challenge of developing tools for the environment of a host language isthat external library modules can add new syntax elements to the host language,making its environment difficult to develop and maintain using tooling based on afixed set of grammar rules. Storm is another example of this kind of extended hostlanguage; i.e., all extensions are defined in the same source file as the hostlanguage. Therefore, each developer has to figure out at least once how theirpieces of code are being parsed.This thesis introduces a new, cursor-centered, filtered syntax-tree visualization forStorm as a side panel in the popular Emacs editor. The visualization is centeredaround the developer’s cursor position, limited to the smallest enclosing multi-lineconstruct, and rendered via a grammar-agnostic renderer that works directly withthe structural characteristics of the syntactic parse trees instead of working withthe names of individual grammatical rules. The editor renders the resulting syntaxtree as a tree view with bidirectional links between source code and syntax treenodes, as well as a direct link to the Storm documentation buffer.