for FORTH like synthesis environment you will want to check out SAPF! (by James McCartney author of SuperCollider) https://github.com/lfnoise/sapf

Wow, I never saw this! I like APL/J/Uiua, so this is perfect. Uiua is both stack and array based. Thanks!

concatenative code is sort of a natural fit for audio in terms of representing signal flow...