in addition to what Jakob said:
> Think for example of micropython or armpit-scheme - those are able to
> run on many microtrollers, I personally run them on a STM32F4 that's
> quite powerful (1MB flash, 200KB RAM) - pretty good for a
I compiled miniPicoLisp here on an STM32F4-Discovery. Works almost
without changes, basically I removed only the command line parsing
stuff, and decreased the allocation size from 1 MB to 32 kB.
As miniPicoLisp now can compile Lisp expressions to C code (see also
http://picolisp.com/wiki/?miniCodeROM), you can incrementally test Lisp
functions in the 196 kB of RAM and then move them to ROM.