The closest Standard Markdown provides is the re2c "source" that gets converted: https://github.com/jgm/stmd/blob/master/src/scanners.re https://github.com/jgm/

The closest Standard Markdown provides is the re2c "source" that gets converted: https://github.com/jgm/stmd/blob/master/src/scanners.re https://github.com/jgm/stmd/blob/master/src/scanners.re I agree that a universal PEG would be great, perhaps this is the project to base that grammar on.