( -- )
( R: i * x
Empty the return stack, store zero in SOURCE-ID
if it is
present, make the user input device the input source, and enter
interpretation state. Do not display a message. Repeat the
- Accept a line from the input source into the input buffer,
set >IN to zero, and interpret.
- Display the implementation-defined system prompt if in
interpretation state, all processing has been completed,
and no ambiguous condition exists.