Haskell implementation of Scheme interpreter from Abelson and Sussman's SICP.
Back in 200x, I ran a study group for the classic comp sci text, "Structure and Interpretation of Computer Programs" by Abelson and Sussman. The book's website, including the full text, is at https://mitpress.mit.edu/sicp/.
Over the course of the book, the authors build a Scheme interpreter in Scheme from first principles. As added fun for the study group, I built the interpreter in Haskell instead of Scheme using the same principles. The result is what you're looking at now.