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"""An in-process qt console app."""
import os
import sys
import tornado
from IPython.lib import guisupport
from qtconsole.inprocess import QtInProcessKernelManager
from qtconsole.rich_ipython_widget import RichIPythonWidget
def print_process_id():
"""Print the process id."""
print("Process ID is:", os.getpid())
def init_asyncio_patch():
"""set default asyncio policy to be compatible with tornado
Tornado 6 (at least) is not compatible with the default
asyncio implementation on Windows
Pick the older SelectorEventLoopPolicy on Windows
if the known-incompatible default policy is in use.
do this as early as possible to make it a low priority and overridable
ref: https://github.com/tornadoweb/tornado/issues/2608
FIXME: if/when tornado supports the defaults in asyncio,
remove and bump tornado requirement for py38
"""
if (
sys.platform.startswith("win")
and sys.version_info >= (3, 8)
and tornado.version_info < (6, 1)
):
import asyncio
try:
from asyncio import WindowsProactorEventLoopPolicy, WindowsSelectorEventLoopPolicy
except ImportError:
pass
# not affected
else:
if type(asyncio.get_event_loop_policy()) is WindowsProactorEventLoopPolicy:
# WindowsProactorEventLoopPolicy is not compatible with tornado 6
# fallback to the pre-3.8 default of Selector
asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())
def main():
"""The main entry point."""
# Print the ID of the main process
print_process_id()
init_asyncio_patch()
app = guisupport.get_app_qt4()
# Create an in-process kernel
# >>> print_process_id()
# will print the same process ID as the main process
kernel_manager = QtInProcessKernelManager()
kernel_manager.start_kernel()
kernel = kernel_manager.kernel
kernel.gui = "qt4"
kernel.shell.push({"foo": 43, "print_process_id": print_process_id})
kernel_client = kernel_manager.client()
kernel_client.start_channels()
def stop():
kernel_client.stop_channels()
kernel_manager.shutdown_kernel()
app.exit()
control = RichIPythonWidget()
control.kernel_manager = kernel_manager
control.kernel_client = kernel_client
control.exit_requested.connect(stop)
control.show()
guisupport.start_event_loop_qt4(app)
if __name__ == "__main__":
main()
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