cpython/Lib/curses/wrapper.py

"""curses.wrapper

Contains one function, wrapper(), which runs another function which
should be the rest of your curses-based application.  If the
application raises an exception, wrapper() will restore the terminal
to a sane state so you can read the resulting traceback.

"""

import sys, curses

def wrapper(func, *rest):
    """Wrapper function that initializes curses and calls another function,
    restoring normal keyboard/screen behavior on error.
    The callable object 'func' is then passed the main window 'stdscr'
    as its first argument, followed by any other arguments passed to
    wrapper().
    """

    res = None
    try:
        # Initialize curses
        stdscr=curses.initscr()

        # Turn off echoing of keys, and enter cbreak mode,
        # where no buffering is performed on keyboard input
        curses.noecho()
        curses.cbreak()

        # In keypad mode, escape sequences for special keys
        # (like the cursor keys) will be interpreted and
        # a special value like curses.KEY_LEFT will be returned
        stdscr.keypad(1)

        # Start color, too.  Harmless if the terminal doesn't have
        # color; user can test with has_color() later on.  The try/catch
        # works around a minor bit of over-conscientiousness in the curses
        # module -- the error return from C start_color() is ignorable.
        try:
            curses.start_color()
        except:
            pass

        res = apply(func, (stdscr,) + rest)
    except:
        # In the event of an error, restore the terminal
        # to a sane state.
        stdscr.keypad(0)
        curses.echo()
        curses.nocbreak()
        curses.endwin()

        # Pass the exception upwards
        (exc_type, exc_value, exc_traceback) = sys.exc_info()
        raise exc_type, exc_value, exc_traceback
    else:
        # Set everything back to normal
        stdscr.keypad(0)
        curses.echo()
        curses.nocbreak()
        curses.endwin()          # Terminate curses

        return res