You got it basically right, a few small corrections:
Replace the word "stack" with "memory buffer" or "tape" everywhere. "Out" represents STDOUT, there is the "." command for printing (and "," for reading from STDIN).
Ah. I thought "." must be printing (as it's something similar to that in Forth [guess it's ".s" though not "."]), but I was confused by the comma because I didn't understand how you'd be reading from stdin here. Actually I'm still confused. What are you reading in?
Replace the word "stack" with "memory buffer" or "tape" everywhere. "Out" represents STDOUT, there is the "." command for printing (and "," for reading from STDIN).
Thanks!