Norman Ramsey has implemented Lua as an extension language for ML, this included actually writing a Lua interpreter not FFI-ing to the standard Lua. He has a series of good papers about the mechanics of exposing the API of an application to the scripting language. The code itself is available as part of the C-- compiler suite. Clean has Esther which is similar in spirit with a paper describing its implementation, the code is in the standard distribution of Clean though I think it has diverged a bit from the paper. Finally if you end up considering Forth, Jerzy Karczmarczuk has a nice paper describing implementations of stack languages very succinctly in Haskell. http://www.cs.tufts.edu/~nr/ http://www.win.tue.nl/ipa/archive/falldays2003/vWeA2003-Esther.pdf http://users.info.unicaen.fr/~karczma/arpap/Fdpe02/fumach.pdf