Abstract Syntax Contextualization Framework for Debugging Attribute Grammar Specifications

Abstract

In this thesis, we explore an aspect of debugging attribute grammar (AG) specifications. AG frameworks in themselves are high-level languages that allow a programmer to specify the syntax rules and semantics of a new programming language. The debugging of AG specifications is often done by interactively traversing abstract syntax trees (ASTs) that represent a parsed program in a metaprogram. The goal of such debugging is to find AG specifications with semantic rules that observe correct inputs but incorrect outputs—the possible bugs of AG specifications we consider.

For large programs, ASTs may be difficult to understand by a programmer; graphically rendering ASTs in a debugging interface is challenging and still does not make it straightforwardly easy to understand ASTs relative to source code. Resultantly, we propose a textual way to use source and source-like syntax to represent the location of a navigated-to AST node relative to its position in an entire AST and highlight any notable features of the tree, such as the application of rewrite rules. This contextualization framework of abstract syntax tree nodes has been prototyped to work on Silver [1] specifications, but it is applicable to any AG framework since it only relies on the core features of the AG paradigm itself.