Forsp has:

• An S-Expression syntax like Lisp
• Function abstraction like Lisp
• Function application like Forth
• An environment structure like Lisp
• Lexically-scoped closures like Lisp (Scheme)
• Cons-cells / lists / atoms like Lisp
• A value/operand stack like Forth
• An ability to express the Lambda Calculus
• A Call-By-Push-Value evaluation order
• Only 3 syntax special forms: ’ ^ $
• Only 1 eval-time special form: quote
• Only 10 primitive functions need to self-implement
• Ability to self-implement in very little code

It’s evaluator is very simple. I suspect simpler than a McCarthy Lisp eval() function, but I haven’t defined a “simplicity function”, so you can be the judge.

In contrast to Lisp, apply() is trivial in Forsp, and instead we have a core function called compute()

GitHub