"""
Created on 4 May 2013

@author: mike
"""

class ValidityRoutines(object):
    """Class to hold all validation routines, such as type checking"""

    def type_check(self, value, valid_type):
        """Checks that value is an instance of valid_type, and returns value if it is, or throws a TypeError otherwise
        """
        if not isinstance(value, valid_type):
            print(repr(valid_type), repr(type(value).__name__))
            raise TypeError(self.__class__.__name__ + " expected " +
                            valid_type.__name__ + ", not " + type(value).__name__)
        return value

    def class_check(self, klass, valid_class):
        """Checks that class is an instance of valid_class, and returns klass if it is, or throws a TypeError otherwise
        """
        if not issubclass(klass, valid_class):
            raise TypeError(self.__class__.__name__ + " expected " +
                            valid_class.__name__ + ", not " + klass.__name__)
        return klass

    def confirm(assertion, error):
        """Acts like an assertion, but will not be disabled when __debug__ is disabled"""
        if not assertion:
            if error is None:
                error = "An unspecified Assertion was not met in " + self.__class__.__name__
            raise AssertionError(error)