Alan Post wrote: It's at https://github.com/AboutUs/kiwi/blob/master/src/syntax.leg Get peg/leg from http://piumarta.com/software/peg/ I just tried it and already found a bug on the first Hello World (it surrounds headers inside paragraphs). It strangely converts templates into underscored words. They may be expecting some other parser piece to restore it. I'm pretty sure there are corner cases in the preprocessor (eg. just looking at the peg file they don't handle mixed case noincludes), but I don't think that should need to be handled by the parser itself. The grammar looks elegant. I doubt it can really handle full wikitext. But it would be so nice if it did...