Overhauls the mechanics of schema validation

Yippie, that makes the code more lightweight and much easier to
understand.

cerberus/__init__.py

@@ -8,20 +8,68 @@
 
 """
 
+from typing import Dict, Optional, Tuple, Union
+
 import pkg_resources
 
-from cerberus.validator import DocumentError, Validator
-from cerberus.schema import rules_set_registry, schema_registry, SchemaError
-from cerberus.utils import TypeDefinition
+from cerberus.base import (
+ rules_set_registry,
+ schema_registry,
+ DocumentError,
+ TypeDefinition,
+ UnconcernedValidator,
+)
+from cerberus.validator import Validator
+from cerberus.schema import SchemaError
 
 
 __version__ = pkg_resources.get_distribution('Cerberus').version
 
+
+def validator_factory(
+ name: str,
+ bases: Union[type, Tuple[type], None] = None,
+ namespace: Optional[Dict] = None,
+ validated_schema: bool = True,
+) -> type:
+ """ Dynamically create a :class:`~cerberus.Validator` subclass.
+ Docstrings of mixin-classes will be added to the resulting
+ class' one if ``__doc__`` is not in :obj:`namespace`.
+
+ :param name: The name of the new class.
+ :param bases: Class(es) with additional and overriding attributes.
+ :param namespace: Attributes for the new class.
+ :param validated_schema: Indicates that schemas that are provided to the validator
+ are to be validated.
+ :return: The created class.
+ """
+
+ validator_class = Validator if validated_schema else UnconcernedValidator
+
+ if namespace is None:
+ namespace = {}
+
+ if bases is None:
+ computed_bases = (validator_class,)
+ elif isinstance(bases, tuple) and validator_class not in bases:
+ computed_bases = bases + (validator_class,) # type: ignore
+ else:
+ computed_bases = (bases, validator_class) # type: ignore
+
+ docstrings = [x.__doc__ for x in computed_bases if x.__doc__]
+ if len(docstrings) > 1 and '__doc__' not in namespace:
+ namespace.update({'__doc__': '\n'.join(docstrings)})
+
+ return type(name, computed_bases, namespace)
+
+
 __all__ = [
  DocumentError.__name__,
  SchemaError.__name__,
  TypeDefinition.__name__,
+ UnconcernedValidator.__name__,
  Validator.__name__,
  'schema_registry',
  'rules_set_registry',
+ validator_factory.__name__,
 ]