SRFI 220: Line directives

by Lassi Kortela

status: draft (2021-02-09)

keywords: Reader Syntax


Many language-agnostic programming tools rely on specially formatted source code comments to annotate the code with metadata. Such "magic comments" are hard for both humans and computers to parse reliably, as the purpose of a comment is to be free-form text that is not interpreted by machine.

This SRFI extends the standard Scheme directive syntax (#!) to support line directives. They look like magic comments to language-agnostic tools but read as S-expressions in Scheme, combining the portability of magic comments with the well-defined syntax and easy parsing of ordinary Scheme code.