magic.py 文件源码

def magics_class(cls):
    """Class decorator for all subclasses of the main Magics class.

    Any class that subclasses Magics *must* also apply this decorator, to
    ensure that all the methods that have been decorated as line/cell magics
    get correctly registered in the class instance.  This is necessary because
    when method decorators run, the class does not exist yet, so they
    temporarily store their information into a module global.  Application of
    this class decorator copies that global data to the class instance and
    clears the global.

    Obviously, this mechanism is not thread-safe, which means that the
    *creation* of subclasses of Magic should only be done in a single-thread
    context.  Instantiation of the classes has no restrictions.  Given that
    these classes are typically created at IPython startup time and before user
    application code becomes active, in practice this should not pose any
    problems.
    """
    cls.registered = True
    cls.magics = dict(line = magics['line'],
                      cell = magics['cell'])
    magics['line'] = {}
    magics['cell'] = {}
    return cls