ipython/IPython/frontend.py at master · wyom/ipython · GitHub

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"""

Shim to maintain backwards compatibility with old frontend imports.

We have moved all contents of the old `frontend` subpackage into top-level

subpackages (`html`, `qt` and `terminal`), and flattened the notebook into

just `IPython.html`, formerly `IPython.frontend.html.notebook`.

This will let code that was making `from IPython.frontend...` calls continue

working, though a warning will be printed.

"""

#-----------------------------------------------------------------------------

# Distributed under the terms of the Modified BSD License.

# The full license is in the file COPYING.txt, distributed with this software.

#-----------------------------------------------------------------------------

# Imports

#-----------------------------------------------------------------------------

from __future__ import print_function

# Stdlib

import sys

import types

from warnings import warn

warn("The top-level `frontend` package has been deprecated. "

"All its subpackages have been moved to the top `IPython` level.")

#-----------------------------------------------------------------------------

# Class declarations

#-----------------------------------------------------------------------------

class ShimModule(types.ModuleType):

def __init__(self, *args, **kwargs):

self._mirror = kwargs.pop("mirror")

super(ShimModule, self).__init__(*args, **kwargs)

def __getattr__(self, key):

# Use the equivalent of import_item(name), see below

name = "%s.%s" % (self._mirror, key)

# NOTE: the code below is copied *verbatim* from

# importstring.import_item. For some very strange reason that makes no

# sense to me, if we call it *as a function*, it doesn't work. This

# has something to do with the deep bowels of the import machinery and

# I couldn't find a way to make the code work as a standard function

# call. But at least since it's an unmodified copy of import_item,

# which is used extensively and has a test suite, we can be reasonably

# confident this is OK. If anyone finds how to call the function, all

# the below could be replaced simply with:

# from IPython.utils.importstring import import_item

# return import_item('MIRROR.' + key)

parts = name.rsplit('.', 1)

if len(parts) == 2:

# called with 'foo.bar....'

package, obj = parts

module = __import__(package, fromlist=[obj])

try:

pak = module.__dict__[obj]

except KeyError:

raise AttributeError(obj)

return pak

else:

# called with un-dotted string

return __import__(parts[0])

# Unconditionally insert the shim into sys.modules so that further import calls

# trigger the custom attribute access above

sys.modules['IPython.frontend.html.notebook'] = ShimModule('notebook', mirror='IPython.html')

sys.modules['IPython.frontend'] = ShimModule('frontend', mirror='IPython')

ipython/IPython/frontend.py at master · wyom/ipython · GitHub

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