Edit File: converters.cpython-37.pyc
B �.`� � @ sp d Z ddlmZmZmZ ddlmZ ddlmZm Z m Z esLddl Z ddl Z ddd gZ d d� Zedfd d �ZdS ) z Commonly useful converters. � )�absolute_import�division�print_function� )�PY2)�NOTHING�Factory�pipeNr �optional�default_if_nonec s� � fdd�}t s�d}yt�� �}W n ttfk r: Y nX |r�t|j�� �}|rz|d jtj j k rzt j |d j |j d< |jtjj k r�t j |j |j d< |S )aO A converter that allows an attribute to be optional. An optional attribute is one which can be set to ``None``. Type annotations will be inferred from the wrapped converter's, if it has any. :param callable converter: the converter that is used for non-``None`` values. .. versionadded:: 17.1.0 c s | d kr d S � | �S )N� )�val)� converterr �@/opt/alt/python37/lib/python3.7/site-packages/attr/converters.py�optional_converter% s z$optional.<locals>.optional_converterNr r �return)r �inspect� signature� ValueError� TypeError�list� parameters�values� annotation� Parameter�empty�typing�Optional�__annotations__�return_annotation� Signature)r r �sig�paramsr )r r r s c sv � t kr|dkrtd��� t k r0|dk r0td��|dk r@t|�� t� t�rf� jrXtd��� fdd�}n � fdd�}|S )a� A converter that allows to replace ``None`` values by *default* or the result of *factory*. :param default: Value to be used if ``None`` is passed. Passing an instance of `attr.Factory` is supported, however the ``takes_self`` option is *not*. :param callable factory: A callable that takes no parameters whose result is used if ``None`` is passed. :raises TypeError: If **neither** *default* or *factory* is passed. :raises TypeError: If **both** *default* and *factory* are passed. :raises ValueError: If an instance of `attr.Factory` is passed with ``takes_self=True``. .. versionadded:: 18.2.0 Nz(Must pass either `default` or `factory`.z5Must pass either `default` or `factory` but not both.z1`takes_self` is not supported by default_if_none.c s | d k r | S � � � S )N)�factory)r )�defaultr r �default_if_none_convertera s z2default_if_none.<locals>.default_if_none_converterc s | d k r | S � S )Nr )r )r$ r r r% i s )r r r � isinstanceZ takes_selfr )r$ r# r% r )r$ r r > s )�__doc__� __future__r r r �_compatr �_maker r r r r �__all__r r r r r r �<module> s '