There's also an interesting book "A model implementation of standard Pascal" - not by Wirth - that implements an ISO Standard Pascal compiler in Standard Pascal, written as a "literate program" with copious descriptions of every single aspect. Basically, the entire book is one large program in which non-code is interspersed as very long multiline comments.

I couldn't find it available for download anywhere, but Internet Archive has a version of it in the library that can be checked out for free: https://archive.org/details/modelimplementat0000wels/page/n9...