Class ReverseMapProcessor

lantz/processors.py:275–301

Processor to map the function parameter values. The syntax is equal to `Processor` except that a dict is used as mapping table. Examples:: >>> conv = ReverseMapProcessor({True: 42}) >>> conv(42) True

class ReverseMapProcessor(Processor):
    """Processor to map the function parameter values.

    The syntax is equal to `Processor` except that a dict is used as
    mapping table.

    Examples::

        >>> conv = ReverseMapProcessor({True: 42})
        >>> conv(42)
        True
    """

    #: Shared cache of reversed dictionaries indexed by the id()
    __reversed_cache = {}

    @classmethod
    def to_callable(cls, obj):
        if isinstance(obj, dict):
            obj = cls.__reversed_cache.setdefault(id(obj),
                                                  {value: key for key, value
                                                   in obj.items()})
            return get_mapping(obj)
        if isinstance(obj, set):
            return check_membership(obj)
        raise TypeError('ReverseMapProcessor argument must be a dict or a callable, '
                        'not {}'.format(obj))


class RangeProcessor(Processor):