Start an interactive Python REPL loop using the embedded Python
interpreter. The interpreter first imports janus as below.
from janus import *
So, we can do
?- py_shell.
...
>>> query_once("writeln(X)", {"X":"Hello world"})
Hello world
{'truth': True}
If possible, we enable command line editing using the GNU readline
library.
When used in an environment where Prolog does not use the file
handles 0,1,2 for the standard streams, e.g., in swipl-win,
Python's I/O is rebound to use Prolog's I/O. This includes Prolog's
command line editor, resulting in a mixed history of Prolog and
Pythin commands.
