Incorporating shells in your own scripts and programs

Sometimes, there is a need to incorporate a read-eval-print loop (REPL), similar to Python's interactive session, inside of your own software. This allows for easier experimentation with your code and inspection of its internal state. The simplest module that allows for emulating Python's interactive interpreter already comes with the standard library and is named code.

The script that starts interactive sessions consists of one import and single function call:

import code
code.interact()

You can easily do some minor tuning, such as modify a prompt value or add banner and exit messages, but anything more fancy will require a lot more work. If you want to have more features, such as code highlighting, completion, or direct access to the system shell, it is always better to use something that was already built by someone. Fortunately, all of the interactive shells that were mentioned in the previous section can be embedded in your own program as easily as the code module.

The following are examples of how to invoke all of the previously mentioned shells inside of your code:

# Example for IPython
import IPython
IPython.embed()

# Example for bpython
import bpython
bpython.embed()

# Example for ptpython
from ptpython.repl import embed
embed(globals(), locals())