gBASIC. `help` for prompt commands, `quit` to leave.
> do = "yes"
parse error at <prompt>:1:4: syntax error, unexpected OP_EQ, expecting NEWLINE -- 'do' is a reserved word and cannot be used as a name
> to = 10
parse error at <prompt>:1:1: syntax error, unexpected TO, expecting end of file -- 'to' is a reserved word and cannot be used as a name
> new = 1
parse error at <prompt>:1:1: syntax error, unexpected NEW, expecting end of file -- 'new' is a reserved word and cannot be used as a name
> end = 10
> end
10
> next = end + 1
> next
11
> list = 5
> list
  1  end = 10
  2  next = end + 1
  3  list = 5
> ? list
5
> quit
Your program was not saved; `recover` will bring it back next time.
