CalculatorDemoDriver.py

#!/usr/bin/env python

"""
NOTE: This worked when it was written, but not with recent
      versions of wxPython (at least on a Mac)
      I suspect that it would have to be re-factored
      to put the GUI in the main thread, and star a secondary thread to
      interact with the user.

Demo of how to drive a wxPython app from another script:

one thread to do the driving, one thread to run the Calculator:

the primary thread runs the GUI - - it gets "locked up" with the mainloop.

the secondary thread is used to do things outside the GUI. In this
case, a simple pause and sending commands now and then. The commands are put
on the event loop with a wx.CallAfter() call.

"""
from __future__ import (division, unicode_literals, print_function)

import threading

import wx

import CalculatorDemo


class GUI_Thread(threading.Thread):
    """
    class to create a thread to run the GUI in

    this should allow the command line to stay active in the main thread,
    while the mainloop is running in this thread.

    """
    def run(self):
        """
        run starts up mainloop of the wx.App
        """
        #Create the application
        self.app = wx.App(False)
        self.calculator = CalculatorDemo.MainFrame(None)
        self.calculator.Show()
        self.app.MainLoop()


# create and start the thread for the GUI
gui_thread = GUI_Thread()
gui_thread.start()

# the computer object:
#computer = gui_thread.calculator.calcPanel.ComputeExpression

# now we have control back -- start a loop for user input
print("enter expressions to calculate: enter to evaluate")
print("hit ctrl+C to exit")
while True:
    expr = input()
    gui_thread.calculator.ComputeExpression(expr)