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cpython/Lib/lib-stdwin/mainloop.py
1991-11-19 20:41:07 +00:00

74 lines
1.7 KiB
Python

# Standard main loop for *all* STDWIN applications.
# This requires that applications:
# - register their windows on creation and unregister them when closed
# - have a 'dispatch' function as a window member
import stdwin, stdwinq
from stdwinevents import *
# List of windows known to the main loop.
#
windows = []
# Function to register a window.
#
def register(win):
# First test the dispatch function by passing it a null event --
# this catches registration of unconforming windows.
win.dispatch(WE_NULL, win, None)
if win not in windows:
windows.append(win)
# Function to unregister a window.
# It is not an error to unregister an already unregistered window
# (this is useful for cleanup actions).
#
def unregister(win):
if win in windows:
windows.remove(win) # Not in 0.9.1
# 0.9.1 solution:
#for i in range(len(windows)):
# if windows[i] = win:
# del windows[i]
# break
# Interfaces used by WindowSched.
#
def countwindows():
return len(windows)
#
def anywindow():
if windows:
return windows[0]
else:
return None
# Event processing main loop.
# Return when there are no windows left, or when an unhandled
# exception occurs. (It is safe to restart the main loop after
# an unsuccessful exit.)
# Python's stdwin.getevent() turns WE_COMMAND/WC_CANCEL events
# into KeyboardInterrupt exceptions; these are turned back in events.
#
def mainloop():
while windows:
try:
dispatch(stdwinq.getevent())
except KeyboardInterrupt:
dispatch(WE_COMMAND, stdwin.getactive(), WC_CANCEL)
# Dispatch a single event.
# Windows not in the windows list don't get their events:
# events for such windows are silently ignored.
#
def dispatch(event):
if event[1] in windows:
event[1].dispatch(event)