Source code for reprit.base

from collections import (OrderedDict,
                         abc)
from inspect import (_ParameterKind,
                     signature as _signature)
from types import MethodType as _MethodType
from typing import (Iterable as _Iterable,
                    Union as _Union)

from . import (seekers as _seekers,
               serializers as _serializers)
from .core.hints import (Constructor as _Constructor,
                         Domain as _Domain,
                         Initializer as _Initializer,
                         Map as _Map)
from .hints import (ArgumentSerializer as _ArgumentSerializer,
                    FieldSeeker as _FieldSeeker)


[docs]def generate_repr(method: _Union[_Constructor, _Initializer], *, argument_serializer: _ArgumentSerializer = _serializers.simple, field_seeker: _FieldSeeker = _seekers.simple, prefer_keyword: bool = False, skip_defaults: bool = False, with_module_name: bool = False) -> _Map[_Domain, str]: """ Generates ``__repr__`` method based on constructor/initializer parameters. We are assuming that no parameters data get thrown away during instance creation, so we can re-create it after. :param method: constructor/initializer method which parameters will be used in resulting representation. :param argument_serializer: function that serializes argument to string. :param field_seeker: function that re-creates parameter value based on class instance and name. :param prefer_keyword: flag that specifies if positional-or-keyword parameters should be outputted as keyword ones when possible. :param skip_defaults: flag that specifies if optional parameters with default arguments should be skipped. :param with_module_name: flag that specifies if module name should be added. >>> from reprit.base import generate_repr >>> class Person: ... def __init__(self, name, *, address=None): ... self.name = name ... self.address = address ... __repr__ = generate_repr(__init__) >>> Person('Adrian') Person('Adrian', address=None) >>> Person('Mary', address='Somewhere on Earth') Person('Mary', address='Somewhere on Earth') >>> class ScoreBoard: ... def __init__(self, first, *rest): ... self.first = first ... self.rest = rest ... __repr__ = generate_repr(__init__, ... prefer_keyword=True) >>> ScoreBoard(1) ScoreBoard(first=1) >>> ScoreBoard(1, 40) ScoreBoard(1, 40) >>> class Student: ... def __init__(self, name, group): ... self.name = name ... self.group = group ... __repr__ = generate_repr(__init__, ... with_module_name=True) >>> Student('Kira', 132) reprit.base.Student('Kira', 132) >>> Student('Naomi', 248) reprit.base.Student('Naomi', 248) >>> from reprit import seekers >>> class Account: ... def __init__(self, id_, *, balance=0): ... self.id = id_ ... self.balance = balance ... __repr__ = generate_repr(__init__, ... field_seeker=seekers.complex_) >>> Account(1) Account(1, balance=0) >>> Account(100, balance=-10) Account(100, balance=-10) >>> import json >>> class Object: ... def __init__(self, value): ... self.value = value ... def serialized(self): ... return json.dumps(self.value) ... @classmethod ... def from_serialized(cls, serialized): ... return cls(json.loads(serialized)) ... __repr__ = generate_repr(from_serialized) >>> Object.from_serialized('0') Object.from_serialized('0') >>> Object.from_serialized('{"key": "value"}') Object.from_serialized('{"key": "value"}') """ if with_module_name: def to_class_name(cls: type) -> str: return cls.__module__ + '.' + cls.__qualname__ else: def to_class_name(cls: type) -> str: return cls.__qualname__ unwrapped_method = (method.__func__ if isinstance(method, (classmethod, staticmethod)) else method) method_name = unwrapped_method.__name__ parameters = OrderedDict(_signature(unwrapped_method).parameters) if method_name in ('__init__', '__new__'): # remove `cls`/`self` parameters.popitem(0) def __repr__(self: _Domain) -> str: return (to_class_name(type(self)) + '(' + ', '.join(to_arguments_strings(self)) + ')') else: if isinstance(method, classmethod): # remove `cls` parameters.popitem(0) def __repr__(self: _Domain) -> str: return (to_class_name(type(self)) + '.' + method_name + '(' + ', '.join(to_arguments_strings(self)) + ')') variadic_positional = next( (parameter for parameter in parameters.values() if parameter.kind is _ParameterKind.VAR_POSITIONAL), None) to_keyword_string = '{}={}'.format def to_arguments_strings(object_: _Domain) -> _Iterable[str]: variadic_positional_unset = ( variadic_positional is None or not field_seeker(object_, variadic_positional.name)) positional_or_keyword_is_keyword = (prefer_keyword and variadic_positional_unset) for name, parameter in parameters.items(): field = field_seeker(object_, name) if isinstance(field, _MethodType) and field.__self__ is object_: field = field() kind = parameter.kind show_parameter = ( not skip_defaults or field is not parameter.default or (not variadic_positional_unset and (kind is _ParameterKind.POSITIONAL_ONLY or kind is _ParameterKind.POSITIONAL_OR_KEYWORD))) if show_parameter: if kind is _ParameterKind.POSITIONAL_ONLY: yield argument_serializer(field) elif kind is _ParameterKind.POSITIONAL_OR_KEYWORD: yield (to_keyword_string(name, argument_serializer(field)) if positional_or_keyword_is_keyword else argument_serializer(field)) elif kind is _ParameterKind.VAR_POSITIONAL: yield from ((argument_serializer(field),) # we don't want to exhaust iterator if isinstance(field, abc.Iterator) else map(argument_serializer, field)) elif kind is _ParameterKind.KEYWORD_ONLY: yield to_keyword_string(name, argument_serializer(field)) else: yield from map(to_keyword_string, field.keys(), map(argument_serializer, field.values())) elif (not positional_or_keyword_is_keyword and (kind is _ParameterKind.POSITIONAL_ONLY or kind is _ParameterKind.POSITIONAL_OR_KEYWORD)): positional_or_keyword_is_keyword = True return __repr__