##// END OF EJS Templates
cleanup kernelspec loading...
cleanup kernelspec loading - kernel_selector.set_kernel validates selection and triggers 'spec_changed.Kernel'. It does not start the session anymore. - notebook calls kernel_selector.set_kernel when: - kernelspec is in notebook metadata - session is loaded (e.g. no kernelspec metadata) - notebook starts session, loads metadata on spec_changed.kernel The only case where starting the session is not triggered by spec_changed is on notebook load with no kernel metadata

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contexts.py
71 lines | 2.0 KiB | text/x-python | PythonLexer
# encoding: utf-8
"""
Context managers for temporarily updating dictionaries.
Authors:
* Bradley Froehle
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2012 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Code
#-----------------------------------------------------------------------------
class preserve_keys(object):
"""Preserve a set of keys in a dictionary.
Upon entering the context manager the current values of the keys
will be saved. Upon exiting, the dictionary will be updated to
restore the original value of the preserved keys. Preserved keys
which did not exist when entering the context manager will be
deleted.
Examples
--------
>>> d = {'a': 1, 'b': 2, 'c': 3}
>>> with preserve_keys(d, 'b', 'c', 'd'):
... del d['a']
... del d['b'] # will be reset to 2
... d['c'] = None # will be reset to 3
... d['d'] = 4 # will be deleted
... d['e'] = 5
... print(sorted(d.items()))
...
[('c', None), ('d', 4), ('e', 5)]
>>> print(sorted(d.items()))
[('b', 2), ('c', 3), ('e', 5)]
"""
def __init__(self, dictionary, *keys):
self.dictionary = dictionary
self.keys = keys
def __enter__(self):
# Actions to perform upon exiting.
to_delete = []
to_update = {}
d = self.dictionary
for k in self.keys:
if k in d:
to_update[k] = d[k]
else:
to_delete.append(k)
self.to_delete = to_delete
self.to_update = to_update
def __exit__(self, *exc_info):
d = self.dictionary
for k in self.to_delete:
d.pop(k, None)
d.update(self.to_update)