Small interpreters are my favorite thing to work with in µC's. the 8051 also has a basic that is now open source, and you can get it running by strapping an EPROM on almost any 8051/8031/8052 etc. compatible board with a serial port. Great fun indeed. Glad to see this is still a thing
Fun fact, if you get Intel 8032 chips of a certain era and strap EA for internal ROM you'll find some of them have BASIC52 V1.0 burned in, seems Intel shipped a load as ROMless when they went to BAISC52 V1.1