2.7. fancytypes.Updatable

class Updatable(skip_validation_and_conversion=False, skip_cls_tests=False, **kwargs)

Bases: Checkable

A type that can perform user-defined validations and conversions of a set of parameters upon construction, and that has an updatable subset of attributes.

One cannot construct an instance of the class fancytypes.Updatable without raising an exception. In order to make use of this class, one must create a subclass that inherits from fancytypes.Updatable and then override the class method get_validation_and_conversion_funcs in a way that is consistent with the method’s description.

Parameters:

• skip_validation_and_conversion (bool, optional) –

  Let validation_and_conversion_funcs and core_attrs denote the attributes validation_and_conversion_funcs and core_attrs respectively, both of which being dict objects.

  Let params_to_be_mapped_to_core_attrs denote the dict representation of the constructor parameters excluding the parameters skip_validation_and_conversion and skip_cls_tests, where each dict key key is a different constructor parameter name, excluding the names "skip_validation_and_conversion" and "skip_cls_tests", and params_to_be_mapped_to_core_attrs[key] would yield the value of the constructor parameter with the name given by key.

  If skip_validation_and_conversion is set to False, then for each key key in params_to_be_mapped_to_core_attrs, core_attrs[key] is set to validation_and_conversion_funcs[key] (params_to_be_mapped_to_core_attrs).

  Otherwise, if skip_validation_and_conversion is set to True, then core_attrs is set to params_to_be_mapped_to_core_attrs.copy(). This option is desired primarily when the user wants to avoid potentially expensive deep copies and/or conversions of the dict values of params_to_be_mapped_to_core_attrs, as it is guaranteed that no copies or conversions are made in this case.

• skip_cls_test (bool, optional) –

  If skip_cls_test is set to False, then upon construction, tests will be performed to check whether the class was properly defined. If any of the tests fail, an exception will be raised.

  Otherwise, if skip_cls_test is set to True, these tests will be skipped.

  One should only skip the tests if they are sure that the class is properly defined. Skipping the tests will yield some improvement in performance.

• **kwargs – The remaining constructor parameters.

Methods

get_core_attrs	Return the core attributes.
get_validation_and_conversion_funcs	Return the validation and conversion functions.
update	Update a subset of the core attributes.

Attributes

core_attrs	The "core attributes".
validation_and_conversion_funcs	The validation and conversion functions.

property core_attrs

The “core attributes”.

The keys of core_attrs are the same as the attribute validation_and_conversion_funcs, which is also a dict object.

Note that core_attrs should be considered read-only.

Type:

dict

get_core_attrs(deep_copy=True)

Return the core attributes.

Parameters:

deep_copy (bool, optional) –

Let core_attrs denote the attribute core_attrs, which is a dict object.

If deep_copy is set to True, then a deep copy of core_attrs is returned. Otherwise, a shallow copy of core_attrs is returned.

Returns:

core_attrs – The attribute core_attrs.

Return type:

dict

classmethod get_validation_and_conversion_funcs()

Return the validation and conversion functions.

Returns:

validation_and_conversion_funcs – The attribute validation_and_conversion_funcs.

Return type:

dict

update(new_core_attr_subset_candidate={}, skip_validation_and_conversion=False)

Update a subset of the core attributes.

Parameters:

• new_core_attr_subset_candidate (dict, optional) – A dict object.

• skip_validation_and_conversion (bool, optional) –

  Let validation_and_conversion_funcs and core_attrs denote the attributes validation_and_conversion_funcs and core_attrs respectively, both of which being dict objects.

  If skip_validation_and_conversion is set to False, then for each key key in core_attrs that is also in new_core_attr_subset_candidate, core_attrs[key] is set to validation_and_conversion_funcs[key] (new_core_attr_subset_candidate).

  Otherwise, if skip_validation_and_conversion is set to True, then for each key key in core_attrs that is also in new_core_attr_subset_candidate, core_attrs[key] is set to new_core_attr_subset_candidate[key]. This option is desired primarily when the user wants to avoid potentially expensive deep copies and/or conversions of the dict values of new_core_attr_subset_candidate, as it is guaranteed that no copies or conversions are made in this case.

property validation_and_conversion_funcs

The validation and conversion functions.

The keys of validation_and_conversion_funcs are the names of the constructor parameters, excluding skip_validation_and_conversion if it exists as a construction parameter.

Let core_attrs denote the attribute core_attrs, which is also a dict object.

For each dict key key in core_attrs, validation_and_conversion_funcs[key](core_attrs) is expected to not raise an exception.

Note that validation_and_conversion_funcs should be considered read-only.

Type:

dict