from __future__ import print_function

#
# Create a GUI with a two buttons.
# One (quit) causes the event loop to terminate.
# The other (die) causes the program to exit.
#
try:
    import Tkinter
except ImportError:
    import tkinter as Tkinter

# Our program is pretty generic and can be used in many
# GUI programs.  Templates like these are also known as
# "patterns".  The pattern in this case is to (1) create
# a top-level application, (2) create the user interface
# elements within, and (3) enter the event loop.
def main():
    app = Tkinter.Frame(bg="red")
    app.grid(sticky="nsew")
    make_ui(app)
    app.mainloop()

# make_ui creates the widgets inside a top-level application
# frame.  Here, we define two functions; we then define two
# buttons, each using one of the functions as callback.
# Note that we place them one on top of the other by specifying
# their row positions in a grid.
def make_ui(app):
    def quit_cb(app=app):
        app.quit()
    def die():
        raise SystemExit(1)
    button = Tkinter.Button(app, text="Quit", command=quit_cb)
    button.grid(row=0, column=0, sticky="nsew")
    button = Tkinter.Button(app, text="Die", command=die)
    button.grid(row=1, column=0, sticky="nsew")

if __name__ == "__main__":
    main()
    print("Finished")