A Core Calculus for Documents

Document languages like Markdown , LaTeX , PHP , and Liquid are widely used to generate digital documents like PDFs and web pages. Document languages often come with programming features like variables and macros to help authors write complex documents. However, these document programming features are often designed or implemented in problematic ways, especially by the standards of a modern programming language. For example: LaTeX’s macro system is not hygienic, which can cause macro arguments to conflict w