Software language design and implementation often involve specifications written in various esoteric meta-languages. Language workbenches generally include support for precise name-based navigation when browsing language specifications locally, but such support is lacking when browsing the same specifications online in code repositories.

This paper presents a technique to support precise name-based navigation of language specifications in online repositories using ordinary web browsers. The idea is to generate hyperlinked twins: websites where verbatim copies of specification text are enhanced with hyperlinks between name references and declarations. By generating hyperlinks directly from the name binding analysis used internally in a language workbench, online navigation in hyperlinked twins is automatically consistent with local navigation.

The presented technique has been implemented for the Spoofax language workbench, and used to generate hyperlinked twin websites from various language specifications in Spoofax meta-languages. However, the applicability of the technique is not limited to Spoofax, and developers of other language workbenches could presumably implement similar tooling, to make their language specifications more accessible to those who do not have the workbench installed.

Peter Mosses is professor emeritus at Swansea University, and currently visiting the Programming Languages Group at Delft University of Technology.

His research in semantics stretches back to Strachey’s Programming Research Group at Oxford in the early 1970s, where he contributed to the development of denotational semantics, and implemented SIS, a system for running programs based on their semantics. He was based at Aarhus University, Denmark, from 1976 to 2004.

The main focus of his research has been on pragmatic aspects of formal specifications – especially modularity. This led to the development of action semantics, MSOS (a modular variant of structural operational semantics) and component-based semantics. He is a principal investigator in the PLanCompS project (Programming Language Components and Specifications), He was also the initial coordinator of CoFI, the Common Framework Initiative, which designed the algebraic specification language CASL.