lsst.utils.wrappers Namespace Reference

Classes
class	TemplateMeta

Functions
def	isAttributeSafeToTransfer (name, value)
def	continueClass (cls)
def	inClass (cls, name=None)

Variables
	INTRINSIC_SPECIAL_ATTRIBUTES

Function Documentation

continueClass()

def lsst.utils.wrappers.continueClass

(

cls

)

Re-open the decorated class, adding any new definitions into the original.

For example::

.. code-block:: python

    class Foo:
        pass

    @continueClass
    class Foo:
        def run(self):
            return None

is equivalent to::

.. code-block:: python

    class Foo:
        def run(self):
            return None

.. warning::

    Python's built-in `super` function does not behave properly in classes
    decorated with `continueClass`.  Base class methods must be invoked
    directly using their explicit types instead.

Definition at line 59 of file wrappers.py.

def continueClass(cls):
    """Re-open the decorated class, adding any new definitions into the original.

    For example::

    .. code-block:: python

        class Foo:
            pass

        @continueClass
        class Foo:
            def run(self):
                return None

    is equivalent to::

    .. code-block:: python

        class Foo:
            def run(self):
                return None

    .. warning::

        Python's built-in `super` function does not behave properly in classes
        decorated with `continueClass`.  Base class methods must be invoked
        directly using their explicit types instead.

    """
    orig = getattr(sys.modules[cls.__module__], cls.__name__)
    for name in dir(cls):
        # Common descriptors like classmethod and staticmethod can only be
        # accessed without invoking their magic if we use __dict__; if we use
        # getattr on those we'll get e.g. a bound method instance on the dummy
        # class rather than a classmethod instance we can put on the target
        # class.
        attr = cls.__dict__.get(name, None) or getattr(cls, name)
        if isAttributeSafeToTransfer(name, attr):
            setattr(orig, name, attr)
    return orig

inClass()

def lsst.utils.wrappers.inClass	(		cls,
			name = None
	)

Add the decorated function to the given class as a method.

For example::

.. code-block:: python

    class Foo:
        pass

    @inClass(Foo)
    def run(self):
        return None

is equivalent to::

.. code-block:: python

    class Foo:
        def run(self):
            return None

Standard decorators like ``classmethod``, ``staticmethod``, and
``property`` may be used *after* this decorator.  Custom decorators
may only be used if they return an object with a ``__name__`` attribute
or the ``name`` optional argument is provided.

Definition at line 102 of file wrappers.py.

def inClass(cls, name=None):
    """Add the decorated function to the given class as a method.

    For example::

    .. code-block:: python

        class Foo:
            pass

        @inClass(Foo)
        def run(self):
            return None

    is equivalent to::

    .. code-block:: python

        class Foo:
            def run(self):
                return None

    Standard decorators like ``classmethod``, ``staticmethod``, and
    ``property`` may be used *after* this decorator.  Custom decorators
    may only be used if they return an object with a ``__name__`` attribute
    or the ``name`` optional argument is provided.
    """
    def decorate(func):
        # Using 'name' instead of 'name1' breaks the closure because
        # assignment signals a strictly local variable.
        name1 = name
        if name1 is None:
            if hasattr(func, "__name__"):
                name1 = func.__name__
            else:
                if hasattr(func, "__func__"):
                    # classmethod and staticmethod have __func__ but no __name__
                    name1 = func.__func__.__name__
                elif hasattr(func, "fget"):
                    # property has fget but no __name__
                    name1 = func.fget.__name__
                else:
                    raise ValueError(
                        "Could not guess attribute name for '{}'.".format(func)
                    )
        setattr(cls, name1, func)
        return func
    return decorate

isAttributeSafeToTransfer()

def lsst.utils.wrappers.isAttributeSafeToTransfer	(		name,
			value
	)

Return True if an attribute is safe to monkeypatch-transfer to another
class.

This rejects special methods that are defined automatically for all
classes, leaving only those explicitly defined in a class decorated by
`continueClass` or registered with an instance of `TemplateMeta`.

Definition at line 45 of file wrappers.py.

def isAttributeSafeToTransfer(name, value):
    """Return True if an attribute is safe to monkeypatch-transfer to another
    class.

    This rejects special methods that are defined automatically for all
    classes, leaving only those explicitly defined in a class decorated by
    `continueClass` or registered with an instance of `TemplateMeta`.
    """
    if name.startswith("__") and (value is getattr(object, name, None) or
                                  name in INTRINSIC_SPECIAL_ATTRIBUTES):
        return False
    return True

Variable Documentation

INTRINSIC_SPECIAL_ATTRIBUTES

lsst.utils.wrappers.INTRINSIC_SPECIAL_ATTRIBUTES

Initial value:

=  frozenset((
    "__qualname__",
    "__module__",
    "__metaclass__",
    "__dict__",
    "__weakref__",
    "__class__",
    "__subclasshook__",
    "__name__",
    "__doc__",
))

Definition at line 32 of file wrappers.py.