Add '-m mod : run library module as a script' option.

[bfroehle]

@fperez is very prescient...

Looks like we have a Pull Request coming from you soon :)

Closes gh-1350.

[minrk]

Should 'run_module' come first or last, assuming more than one such code-to-run is given?

I'm fine with a decision of 'behavior undefined' for such situations (which are probably rare), but a public decision would be useful.

[bfroehle]

The python executable only allows one of -c or -m (by terminating the options list). shrug

[minrk]

IPython will not stop parsing args at '-c' or '-m', so if that should happen, more work would need to be done:

$> ipython -m easy_install pyzmq --user
<snip>
[TerminalIPythonApp] Bad config encountered during initialization:
[TerminalIPythonApp] Unrecognized flag: '--user'

[bfroehle]

Well, I don't think there is much that can be done without changing the IPython argument parser. However, it may be possible to one day support syntax like

$ ipython -m easy_install -- pyzmq --user

where the -- separates ipython flags from extra arguments. That is likely beyond the scope of this pull request.

As such, the current patch is useful for running modules which take no arguments, and in the last commit I took the similar sys.argv handling from _exec_file(), which will allow some arguments.

[minrk]

Yes, it will work if no arguments are to be passed, which is already a nice feature.

We already use -- to stop parsing, but even that won't quite work because the first positional argument (the first one past --) is interpreted as file_to_run. This action should probably be skipped if the module is specified.

The relevant line: https://github.com/ipython/ipython/blob/master/IPython/frontend/terminal/ipapp.py#L309

[bfroehle]

Just pushed a small fix so that ipython -m <module> exits after running the module. Interactive mode can be forced with -i as always.

[minrk]

module_to_run and code_to_run should probably be treated the same. Do you want to set a flag inside _file_to_run_changed to use here, rather than explicitly checking for self.module_to_run?

[bfroehle]

So do you mean something like

    def _file_to_run_changed(self, name, old, new):
        something_to_run = True
        ...

    # internal, not-configurable
    interact = Bool(True)
    something_to_run=Bool(False)

   ....

    def initialize(self, argv=None):
        ...
        if self.extra_args and not self.something_to_run:
            self.file_to_run = self.extra_args[0]
        ...

[minrk]

Yes, precisely.

[minrk]

Nice, thanks! Looks good to me.