Fake EOF?

[jdemeyer]

Is there a way for an application to signal to prompt_toolkit that it should pretend an EOF has happened (typically making the application exit)? Something like this works with readline but not with prompt_toolkit:

In [1]: import os; f = open(os.devnull); os.dup2(f.fileno(), 0)

In [2]:      
Traceback (most recent call last):
  File "/usr/local/src/sage-config/local/bin/ipython", line 5, in <module>
    start_ipython()
  File "/usr/local/src/sage-config/local/lib/python2.7/site-packages/IPython/__init__.py", line 119, in start_ipython
    return launch_new_instance(argv=argv, **kwargs)
  File "/usr/local/src/sage-config/local/lib/python2.7/site-packages/traitlets/config/application.py", line 596, in launch_instance
    app.start()
  File "/usr/local/src/sage-config/local/lib/python2.7/site-packages/IPython/terminal/ipapp.py", line 348, in start
    self.shell.mainloop()
  File "/usr/local/src/sage-config/local/lib/python2.7/site-packages/IPython/terminal/interactiveshell.py", line 402, in mainloop
    self.interact()
  File "/usr/local/src/sage-config/local/lib/python2.7/site-packages/IPython/terminal/interactiveshell.py", line 385, in interact
    code = self.prompt_for_code()
  File "/usr/local/src/sage-config/local/lib/python2.7/site-packages/IPython/terminal/interactiveshell.py", line 321, in prompt_for_code
    pre_run=self.pre_prompt, reset_current_buffer=True)
  File "build/bdist.linux-x86_64/egg/prompt_toolkit/interface.py", line 385, in run
    with self.input.raw_mode():
  File "build/bdist.linux-x86_64/egg/prompt_toolkit/input.py", line 69, in raw_mode
    return raw_mode(self.stdin.fileno())
  File "build/bdist.linux-x86_64/egg/prompt_toolkit/terminal/vt100_input.py", line 409, in __init__
    self.attrs_before = termios.tcgetattr(fileno)
error: (25, 'Inappropriate ioctl for device')

My use case is a signal handler forcing the application to exit gracefully.

[takluyver]

cli.exit() is documented as being equivalent to pressing Ctrl-D.

http://python-prompt-toolkit.readthedocs.io/en/latest/pages/reference.html#prompt_toolkit.interface.CommandLineInterface.exit

[jdemeyer]

cli.exit() is documented as being equivalent to pressing Ctrl-D.

But that does not work asynchronously. I want a solution which would work while prompt_toolkit is actually waiting for user input.

[jonathanslenders]

Hi @jdemeyer,
Thanks for this request. I made a pull request that will probably solve the issue: #393

However, I wonder why you would ever dup devnull to fd 0.

[jdemeyer]

However, I wonder why you would ever dup devnull to fd 0.

Because that did the trick for readline :-)

[jonathanslenders]

Closing this now. In prompt_toolkit 2.0, calling get_app().exit() should close the current application. This can be done in any key binding, and works asynchronously. Please open again or create a new issue if this still doesn't work.

[techtonik]

from prompt_toolkit.application.current import get_app

@global_kb.add('f10')  # F10
def quit(event):
    get_app().exit()

This make prompt return None. Not the same as pressing Ctrl+D which raises EOFError.

[jonathanslenders]

get_app().exit(exception=EOFError)

should probably do it.

[techtonik]

It does. Thanks. =)