jacinle.utils.defaults

Module attributes

ARGDEF

A special value to indicate that the default value of an argument will be determined in a deferred manner.

Classes

DefaultsManager	Defaults manager can be used to create program or thread-level registries.
FileOptions	A class that stores options in a single file.

Functions

default_args(func)	A helper function handles the case of "fall-through" default arguments.
gen_get_default()
gen_set_default(cls)
option_context(name[, is_local])
wrap_custom_as_default

Class DefaultsManager

class DefaultsManager

Bases: object

Defaults manager can be used to create program or thread-level registries. One of the typical use case is that you can create an instance of a specific class, and then set it as the default, and then get this instance from elsewhere.

For example:

>>> class Storage(object):
...     def __init__(self, value):
...         self.value = value

>>> storage = Storage(1)
>>> set_defualt_storage(storage)
>>> get_default_storage()  # now you can call this elsewhere.

Another important feature supported by this default manager is that it allows you to have “nested” default registries.

For example:

>>> get_default_storage().value  # -> 1
>>> with Stoage(2).as_default():
...     get_default_storage().value  # -> 2
...     with Storage(3).as_default():
...         get_default_storage().value  # -> 3
...     get_default_storage().value  # -> 2

Similar features have been used commonly in TensorFlow, e.g., tf.Session, tf.Graph.

To create a class with a default registry, use the following:

class Storage(object):
    def __init__(self, value):
        self.value = value

    @defaults_manager.wrap_custom_as_default(is_local=True)
    def as_default(self):  # this is a contextmanager
        yield

get_default_storage = defaults_manager.gen_get_default(Storage)
set_default_storage = defaults_manager.gen_set_default(Storage)

__init__()

__new__(**kwargs)

gen_get_default()

gen_set_default(cls)

set_default(cls, default)

wrap_custom_as_default()

Class FileOptions

class FileOptions

Bases: object

A class that stores options in a single file.

Example

# file: my_module.py
options = FileOptions(__file__, number_to_add=1)

def my_func(x: int) -> int:
    return x + options.number_to_add

# file: my_script.py
import my_module
my_module.options.set(number_to_add=2)
my_module.my_func(1)  # returns 3

__init__(__file__, **init_kwargs)

__new__(**kwargs)

set(**kwargs)

Functions

default_args(func)

A helper function handles the case of “fall-through” default arguments. Suppose we have two functions: f and g, and f calls g. g has a default argument x, e.g., x=1. In many cases, we do not want to specify the default value of x in f. One way to do this is to use None as the default value of x in f, and then check if x is None in g. However this does not handle cases where x can be None in other cases. It also requires additional checks in g. With this decorator, we can simply write x=ARGDEF in f, and then x will be set to 1 in g.

Example

def f(x=ARGDEF):
    g(x)

@default_args
def g(x=1):
    print(x)

f()  # prints 1
f(2)  # prints 2

gen_get_default()

gen_set_default(cls)

option_context(name, is_local=True, **kwargs)

wrap_custom_as_default()