gBASIC. `help` for prompt commands, `quit` to leave.
> for i = 1 to 3
...   print(i)
... next i
1
2
3
> i
3
> for i = 5 to 1
...   print("this never prints")
... next i
> for i = 5 to 1 step -1
...   print(i)
... next i
5
4
3
2
1
> for i = 1 to 3 step 0
...   print(i)
... next i
runtime error at <prompt>:1:1: for step cannot be zero
> quit
Your program was not saved; `recover` will bring it back next time.
