An ugly and incomplete forth-like interpreter in scheme using just a single closure
Calling (forth) in the repl will call forth the interpreter.
Word definitions end with df instead of ;.
You can define a word like so -> : add1 1 + df
2 add1 will remove the 2 from the stack and put 3.
21 12 > if "North" else 12 21 < if "South" else "Canada?" then then will -hopefully- work.
Use .s instead of .S , dup instead of DUP and so on. The code is very incomplete so most things won't work.
If you need a loop, you have to use recursion.. which you can;
: show dup 0 = if "DONE" else dup . 1 - show then df
show 999999999 should print 999999999 999999998 999999997 etc.
: sum swap dup 0 = if drop "DONE" else swap + sum then df
0 12 23 34 45 sum should consume those numbers and put 114 to stack
: fact dup 0 = if drop "DONE" else dup rot * swap 1 - fact then df
: fac 1 swap fact df
5 fac should consume 5 and leave 120
You can pause the forth interpreter by typing pause, or you can exit and destroy the stack and defined words.
Q: Why forth
A: Because it's simple
Q: Why lisp
A: Because it's pretty