Enhancing Functionality with Assistive Error Visualisations in Encore

Sammanfattning: Compiler errors are an inevitable part of software development in compiled languages. Many compilers use very specific phrasing, which can be hard to understand by beginners, or programmers unfamiliar with constructs or concepts that are specific to a language. This is no less true for experimental research languages such as Encore, the language improved in this thesis. Encore introduces type system features seldom used in the mainstream. Modern compilers output messages with a wide target audience, typically both human readers as well as tools that parse error messages and show them inline e.g., as part of an IDE tool chain. Balancing human readability and precision is a difficult tightrope walk. This thesis reports on the design and implementation of an error handler for Encore for the displaying of error messages in a way that specifically targets human readers through systematic use of whitespace and color coding. The new handler also enables the compiler to provide further information, such as suggesting a probable problem fix. As a direct result of this work, the error messages in the Encore compiler have been improved considerably, and there is a clear path for integration of future error messages.