A Core Calculus for Documents

TL;DR

This paper introduces a formal core calculus for document languages that combine passive content and active programming, providing a foundation for designing and analyzing complex document systems.

Contribution

It formalizes document languages as a calculus, enabling better understanding, implementation, and theorem proving for reactive and interactive document features.

Findings

Formalization of document languages as a calculus

Application of calculus to implement reactivity

Theoretical basis for designing new document languages

Abstract

Passive documents and active programs now widely comingle. Document languages include Turing-complete programming elements, and programming languages include sophisticated document notations. However, there are no formal foundations that model these languages. This matters because the interaction between document and program can be subtle and error-prone. In this paper we describe several such problems, then taxonomize and formalize document languages as levels of a document calculus. We employ the calculus as a foundation for implementing complex features such as reactivity, as well as for proving theorems about the boundary of content and computation. We intend for the document calculus to provide a theoretical basis for new document languages, and to assist designers in cleaning up the unsavory corners of existing languages.