signatures.py
819 lines
| 29.1 KiB
| text/x-python
|
PythonLexer
Thomas Kluyver
|
r15137 | """Function signature objects for callables | ||
| Back port of Python 3.3's function signature tools from the inspect module, | ||||
| modified to be compatible with Python 2.6, 2.7 and 3.2+. | ||||
| """ | ||||
| #----------------------------------------------------------------------------- | ||||
| # Python 3.3 stdlib inspect.py is public domain | ||||
| # | ||||
| # Backports Copyright (C) 2013 Aaron Iles | ||||
| # Used under Apache License Version 2.0 | ||||
| # | ||||
| # Further Changes are Copyright (C) 2013 The IPython Development Team | ||||
| # | ||||
| # Distributed under the terms of the BSD License. The full license is in | ||||
| # the file COPYING, distributed as part of this software. | ||||
| #----------------------------------------------------------------------------- | ||||
| from __future__ import absolute_import, division, print_function | ||||
| import itertools | ||||
| import functools | ||||
| import re | ||||
| import types | ||||
| # patch for single-file | ||||
| # we don't support 2.6, so we can just import OrderedDict | ||||
| from collections import OrderedDict | ||||
| __version__ = '0.3' | ||||
| # end patch | ||||
| __all__ = ['BoundArguments', 'Parameter', 'Signature', 'signature'] | ||||
| _WrapperDescriptor = type(type.__call__) | ||||
| _MethodWrapper = type(all.__call__) | ||||
| _NonUserDefinedCallables = (_WrapperDescriptor, | ||||
| _MethodWrapper, | ||||
| types.BuiltinFunctionType) | ||||
| def formatannotation(annotation, base_module=None): | ||||
| if isinstance(annotation, type): | ||||
| if annotation.__module__ in ('builtins', '__builtin__', base_module): | ||||
| return annotation.__name__ | ||||
| return annotation.__module__+'.'+annotation.__name__ | ||||
| return repr(annotation) | ||||
| def _get_user_defined_method(cls, method_name, *nested): | ||||
| try: | ||||
| if cls is type: | ||||
| return | ||||
| meth = getattr(cls, method_name) | ||||
| for name in nested: | ||||
| meth = getattr(meth, name, meth) | ||||
| except AttributeError: | ||||
| return | ||||
| else: | ||||
| if not isinstance(meth, _NonUserDefinedCallables): | ||||
| # Once '__signature__' will be added to 'C'-level | ||||
| # callables, this check won't be necessary | ||||
| return meth | ||||
| def signature(obj): | ||||
| '''Get a signature object for the passed callable.''' | ||||
| if not callable(obj): | ||||
| raise TypeError('{0!r} is not a callable object'.format(obj)) | ||||
| if isinstance(obj, types.MethodType): | ||||
| # In this case we skip the first parameter of the underlying | ||||
| # function (usually `self` or `cls`). | ||||
| sig = signature(obj.__func__) | ||||
| return sig.replace(parameters=tuple(sig.parameters.values())[1:]) | ||||
| try: | ||||
| sig = obj.__signature__ | ||||
| except AttributeError: | ||||
| pass | ||||
| else: | ||||
| if sig is not None: | ||||
| return sig | ||||
| try: | ||||
| # Was this function wrapped by a decorator? | ||||
| wrapped = obj.__wrapped__ | ||||
| except AttributeError: | ||||
| pass | ||||
| else: | ||||
| return signature(wrapped) | ||||
| if isinstance(obj, types.FunctionType): | ||||
| return Signature.from_function(obj) | ||||
| if isinstance(obj, functools.partial): | ||||
| sig = signature(obj.func) | ||||
| new_params = OrderedDict(sig.parameters.items()) | ||||
| partial_args = obj.args or () | ||||
| partial_keywords = obj.keywords or {} | ||||
| try: | ||||
| ba = sig.bind_partial(*partial_args, **partial_keywords) | ||||
| except TypeError as ex: | ||||
| msg = 'partial object {0!r} has incorrect arguments'.format(obj) | ||||
| raise ValueError(msg) | ||||
| for arg_name, arg_value in ba.arguments.items(): | ||||
| param = new_params[arg_name] | ||||
| if arg_name in partial_keywords: | ||||
| # We set a new default value, because the following code | ||||
| # is correct: | ||||
| # | ||||
| # >>> def foo(a): print(a) | ||||
| # >>> print(partial(partial(foo, a=10), a=20)()) | ||||
| # 20 | ||||
| # >>> print(partial(partial(foo, a=10), a=20)(a=30)) | ||||
| # 30 | ||||
| # | ||||
| # So, with 'partial' objects, passing a keyword argument is | ||||
| # like setting a new default value for the corresponding | ||||
| # parameter | ||||
| # | ||||
| # We also mark this parameter with '_partial_kwarg' | ||||
| # flag. Later, in '_bind', the 'default' value of this | ||||
| # parameter will be added to 'kwargs', to simulate | ||||
| # the 'functools.partial' real call. | ||||
| new_params[arg_name] = param.replace(default=arg_value, | ||||
| _partial_kwarg=True) | ||||
| elif (param.kind not in (_VAR_KEYWORD, _VAR_POSITIONAL) and | ||||
| not param._partial_kwarg): | ||||
| new_params.pop(arg_name) | ||||
| return sig.replace(parameters=new_params.values()) | ||||
| sig = None | ||||
| if isinstance(obj, type): | ||||
| # obj is a class or a metaclass | ||||
| # First, let's see if it has an overloaded __call__ defined | ||||
| # in its metaclass | ||||
| call = _get_user_defined_method(type(obj), '__call__') | ||||
| if call is not None: | ||||
| sig = signature(call) | ||||
| else: | ||||
| # Now we check if the 'obj' class has a '__new__' method | ||||
| new = _get_user_defined_method(obj, '__new__') | ||||
| if new is not None: | ||||
| sig = signature(new) | ||||
| else: | ||||
| # Finally, we should have at least __init__ implemented | ||||
| init = _get_user_defined_method(obj, '__init__') | ||||
| if init is not None: | ||||
| sig = signature(init) | ||||
| elif not isinstance(obj, _NonUserDefinedCallables): | ||||
| # An object with __call__ | ||||
| # We also check that the 'obj' is not an instance of | ||||
| # _WrapperDescriptor or _MethodWrapper to avoid | ||||
| # infinite recursion (and even potential segfault) | ||||
| call = _get_user_defined_method(type(obj), '__call__', 'im_func') | ||||
| if call is not None: | ||||
| sig = signature(call) | ||||
| if sig is not None: | ||||
| return sig | ||||
| if isinstance(obj, types.BuiltinFunctionType): | ||||
| # Raise a nicer error message for builtins | ||||
| msg = 'no signature found for builtin function {0!r}'.format(obj) | ||||
| raise ValueError(msg) | ||||
| raise ValueError('callable {0!r} is not supported by signature'.format(obj)) | ||||
| class _void(object): | ||||
| '''A private marker - used in Parameter & Signature''' | ||||
| class _empty(object): | ||||
| pass | ||||
| class _ParameterKind(int): | ||||
| def __new__(self, *args, **kwargs): | ||||
| obj = int.__new__(self, *args) | ||||
| obj._name = kwargs['name'] | ||||
| return obj | ||||
| def __str__(self): | ||||
| return self._name | ||||
| def __repr__(self): | ||||
| return '<_ParameterKind: {0!r}>'.format(self._name) | ||||
| _POSITIONAL_ONLY = _ParameterKind(0, name='POSITIONAL_ONLY') | ||||
| _POSITIONAL_OR_KEYWORD = _ParameterKind(1, name='POSITIONAL_OR_KEYWORD') | ||||
| _VAR_POSITIONAL = _ParameterKind(2, name='VAR_POSITIONAL') | ||||
| _KEYWORD_ONLY = _ParameterKind(3, name='KEYWORD_ONLY') | ||||
| _VAR_KEYWORD = _ParameterKind(4, name='VAR_KEYWORD') | ||||
| class Parameter(object): | ||||
| '''Represents a parameter in a function signature. | ||||
| Has the following public attributes: | ||||
| * name : str | ||||
| The name of the parameter as a string. | ||||
| * default : object | ||||
| The default value for the parameter if specified. If the | ||||
| parameter has no default value, this attribute is not set. | ||||
| * annotation | ||||
| The annotation for the parameter if specified. If the | ||||
| parameter has no annotation, this attribute is not set. | ||||
| * kind : str | ||||
| Describes how argument values are bound to the parameter. | ||||
| Possible values: `Parameter.POSITIONAL_ONLY`, | ||||
| `Parameter.POSITIONAL_OR_KEYWORD`, `Parameter.VAR_POSITIONAL`, | ||||
| `Parameter.KEYWORD_ONLY`, `Parameter.VAR_KEYWORD`. | ||||
| ''' | ||||
| __slots__ = ('_name', '_kind', '_default', '_annotation', '_partial_kwarg') | ||||
| POSITIONAL_ONLY = _POSITIONAL_ONLY | ||||
| POSITIONAL_OR_KEYWORD = _POSITIONAL_OR_KEYWORD | ||||
| VAR_POSITIONAL = _VAR_POSITIONAL | ||||
| KEYWORD_ONLY = _KEYWORD_ONLY | ||||
| VAR_KEYWORD = _VAR_KEYWORD | ||||
| empty = _empty | ||||
| def __init__(self, name, kind, default=_empty, annotation=_empty, | ||||
| _partial_kwarg=False): | ||||
| if kind not in (_POSITIONAL_ONLY, _POSITIONAL_OR_KEYWORD, | ||||
| _VAR_POSITIONAL, _KEYWORD_ONLY, _VAR_KEYWORD): | ||||
| raise ValueError("invalid value for 'Parameter.kind' attribute") | ||||
| self._kind = kind | ||||
| if default is not _empty: | ||||
| if kind in (_VAR_POSITIONAL, _VAR_KEYWORD): | ||||
| msg = '{0} parameters cannot have default values'.format(kind) | ||||
| raise ValueError(msg) | ||||
| self._default = default | ||||
| self._annotation = annotation | ||||
| if name is None: | ||||
| if kind != _POSITIONAL_ONLY: | ||||
| raise ValueError("None is not a valid name for a " | ||||
| "non-positional-only parameter") | ||||
| self._name = name | ||||
| else: | ||||
| name = str(name) | ||||
| if kind != _POSITIONAL_ONLY and not re.match(r'[a-z_]\w*$', name, re.I): | ||||
| msg = '{0!r} is not a valid parameter name'.format(name) | ||||
| raise ValueError(msg) | ||||
| self._name = name | ||||
| self._partial_kwarg = _partial_kwarg | ||||
| @property | ||||
| def name(self): | ||||
| return self._name | ||||
| @property | ||||
| def default(self): | ||||
| return self._default | ||||
| @property | ||||
| def annotation(self): | ||||
| return self._annotation | ||||
| @property | ||||
| def kind(self): | ||||
| return self._kind | ||||
| def replace(self, name=_void, kind=_void, annotation=_void, | ||||
| default=_void, _partial_kwarg=_void): | ||||
| '''Creates a customized copy of the Parameter.''' | ||||
| if name is _void: | ||||
| name = self._name | ||||
| if kind is _void: | ||||
| kind = self._kind | ||||
| if annotation is _void: | ||||
| annotation = self._annotation | ||||
| if default is _void: | ||||
| default = self._default | ||||
| if _partial_kwarg is _void: | ||||
| _partial_kwarg = self._partial_kwarg | ||||
| return type(self)(name, kind, default=default, annotation=annotation, | ||||
| _partial_kwarg=_partial_kwarg) | ||||
| def __str__(self): | ||||
| kind = self.kind | ||||
| formatted = self._name | ||||
| if kind == _POSITIONAL_ONLY: | ||||
| if formatted is None: | ||||
| formatted = '' | ||||
| formatted = '<{0}>'.format(formatted) | ||||
| # Add annotation and default value | ||||
| if self._annotation is not _empty: | ||||
| formatted = '{0}:{1}'.format(formatted, | ||||
| formatannotation(self._annotation)) | ||||
| if self._default is not _empty: | ||||
| formatted = '{0}={1}'.format(formatted, repr(self._default)) | ||||
| if kind == _VAR_POSITIONAL: | ||||
| formatted = '*' + formatted | ||||
| elif kind == _VAR_KEYWORD: | ||||
| formatted = '**' + formatted | ||||
| return formatted | ||||
| def __repr__(self): | ||||
| return '<{0} at {1:#x} {2!r}>'.format(self.__class__.__name__, | ||||
| id(self), self.name) | ||||
| def __hash__(self): | ||||
| msg = "unhashable type: '{0}'".format(self.__class__.__name__) | ||||
| raise TypeError(msg) | ||||
| def __eq__(self, other): | ||||
| return (issubclass(other.__class__, Parameter) and | ||||
| self._name == other._name and | ||||
| self._kind == other._kind and | ||||
| self._default == other._default and | ||||
| self._annotation == other._annotation) | ||||
| def __ne__(self, other): | ||||
| return not self.__eq__(other) | ||||
| class BoundArguments(object): | ||||
| '''Result of `Signature.bind` call. Holds the mapping of arguments | ||||
| to the function's parameters. | ||||
| Has the following public attributes: | ||||
| * arguments : OrderedDict | ||||
| An ordered mutable mapping of parameters' names to arguments' values. | ||||
| Does not contain arguments' default values. | ||||
| * signature : Signature | ||||
| The Signature object that created this instance. | ||||
| * args : tuple | ||||
| Tuple of positional arguments values. | ||||
| * kwargs : dict | ||||
| Dict of keyword arguments values. | ||||
| ''' | ||||
| def __init__(self, signature, arguments): | ||||
| self.arguments = arguments | ||||
| self._signature = signature | ||||
| @property | ||||
| def signature(self): | ||||
| return self._signature | ||||
| @property | ||||
| def args(self): | ||||
| args = [] | ||||
| for param_name, param in self._signature.parameters.items(): | ||||
| if (param.kind in (_VAR_KEYWORD, _KEYWORD_ONLY) or | ||||
| param._partial_kwarg): | ||||
| # Keyword arguments mapped by 'functools.partial' | ||||
| # (Parameter._partial_kwarg is True) are mapped | ||||
| # in 'BoundArguments.kwargs', along with VAR_KEYWORD & | ||||
| # KEYWORD_ONLY | ||||
| break | ||||
| try: | ||||
| arg = self.arguments[param_name] | ||||
| except KeyError: | ||||
| # We're done here. Other arguments | ||||
| # will be mapped in 'BoundArguments.kwargs' | ||||
| break | ||||
| else: | ||||
| if param.kind == _VAR_POSITIONAL: | ||||
| # *args | ||||
| args.extend(arg) | ||||
| else: | ||||
| # plain argument | ||||
| args.append(arg) | ||||
| return tuple(args) | ||||
| @property | ||||
| def kwargs(self): | ||||
| kwargs = {} | ||||
| kwargs_started = False | ||||
| for param_name, param in self._signature.parameters.items(): | ||||
| if not kwargs_started: | ||||
| if (param.kind in (_VAR_KEYWORD, _KEYWORD_ONLY) or | ||||
| param._partial_kwarg): | ||||
| kwargs_started = True | ||||
| else: | ||||
| if param_name not in self.arguments: | ||||
| kwargs_started = True | ||||
| continue | ||||
| if not kwargs_started: | ||||
| continue | ||||
| try: | ||||
| arg = self.arguments[param_name] | ||||
| except KeyError: | ||||
| pass | ||||
| else: | ||||
| if param.kind == _VAR_KEYWORD: | ||||
| # **kwargs | ||||
| kwargs.update(arg) | ||||
| else: | ||||
| # plain keyword argument | ||||
| kwargs[param_name] = arg | ||||
| return kwargs | ||||
| def __hash__(self): | ||||
| msg = "unhashable type: '{0}'".format(self.__class__.__name__) | ||||
| raise TypeError(msg) | ||||
| def __eq__(self, other): | ||||
| return (issubclass(other.__class__, BoundArguments) and | ||||
| self.signature == other.signature and | ||||
| self.arguments == other.arguments) | ||||
| def __ne__(self, other): | ||||
| return not self.__eq__(other) | ||||
| class Signature(object): | ||||
| '''A Signature object represents the overall signature of a function. | ||||
| It stores a Parameter object for each parameter accepted by the | ||||
| function, as well as information specific to the function itself. | ||||
| A Signature object has the following public attributes and methods: | ||||
| * parameters : OrderedDict | ||||
| An ordered mapping of parameters' names to the corresponding | ||||
| Parameter objects (keyword-only arguments are in the same order | ||||
| as listed in `code.co_varnames`). | ||||
| * return_annotation : object | ||||
| The annotation for the return type of the function if specified. | ||||
| If the function has no annotation for its return type, this | ||||
| attribute is not set. | ||||
| * bind(*args, **kwargs) -> BoundArguments | ||||
| Creates a mapping from positional and keyword arguments to | ||||
| parameters. | ||||
| * bind_partial(*args, **kwargs) -> BoundArguments | ||||
| Creates a partial mapping from positional and keyword arguments | ||||
| to parameters (simulating 'functools.partial' behavior.) | ||||
| ''' | ||||
| __slots__ = ('_return_annotation', '_parameters') | ||||
| _parameter_cls = Parameter | ||||
| _bound_arguments_cls = BoundArguments | ||||
| empty = _empty | ||||
| def __init__(self, parameters=None, return_annotation=_empty, | ||||
| __validate_parameters__=True): | ||||
| '''Constructs Signature from the given list of Parameter | ||||
| objects and 'return_annotation'. All arguments are optional. | ||||
| ''' | ||||
| if parameters is None: | ||||
| params = OrderedDict() | ||||
| else: | ||||
| if __validate_parameters__: | ||||
| params = OrderedDict() | ||||
| top_kind = _POSITIONAL_ONLY | ||||
| for idx, param in enumerate(parameters): | ||||
| kind = param.kind | ||||
| if kind < top_kind: | ||||
| msg = 'wrong parameter order: {0} before {1}' | ||||
| msg = msg.format(top_kind, param.kind) | ||||
| raise ValueError(msg) | ||||
| else: | ||||
| top_kind = kind | ||||
| name = param.name | ||||
| if name is None: | ||||
| name = str(idx) | ||||
| param = param.replace(name=name) | ||||
| if name in params: | ||||
| msg = 'duplicate parameter name: {0!r}'.format(name) | ||||
| raise ValueError(msg) | ||||
| params[name] = param | ||||
| else: | ||||
| params = OrderedDict(((param.name, param) | ||||
| for param in parameters)) | ||||
| self._parameters = params | ||||
| self._return_annotation = return_annotation | ||||
| @classmethod | ||||
| def from_function(cls, func): | ||||
| '''Constructs Signature for the given python function''' | ||||
| if not isinstance(func, types.FunctionType): | ||||
| raise TypeError('{0!r} is not a Python function'.format(func)) | ||||
| Parameter = cls._parameter_cls | ||||
| # Parameter information. | ||||
| func_code = func.__code__ | ||||
| pos_count = func_code.co_argcount | ||||
| arg_names = func_code.co_varnames | ||||
| positional = tuple(arg_names[:pos_count]) | ||||
| keyword_only_count = getattr(func_code, 'co_kwonlyargcount', 0) | ||||
| keyword_only = arg_names[pos_count:(pos_count + keyword_only_count)] | ||||
| annotations = getattr(func, '__annotations__', {}) | ||||
| defaults = func.__defaults__ | ||||
| kwdefaults = getattr(func, '__kwdefaults__', None) | ||||
| if defaults: | ||||
| pos_default_count = len(defaults) | ||||
| else: | ||||
| pos_default_count = 0 | ||||
| parameters = [] | ||||
| # Non-keyword-only parameters w/o defaults. | ||||
| non_default_count = pos_count - pos_default_count | ||||
| for name in positional[:non_default_count]: | ||||
| annotation = annotations.get(name, _empty) | ||||
| parameters.append(Parameter(name, annotation=annotation, | ||||
| kind=_POSITIONAL_OR_KEYWORD)) | ||||
| # ... w/ defaults. | ||||
| for offset, name in enumerate(positional[non_default_count:]): | ||||
| annotation = annotations.get(name, _empty) | ||||
| parameters.append(Parameter(name, annotation=annotation, | ||||
| kind=_POSITIONAL_OR_KEYWORD, | ||||
| default=defaults[offset])) | ||||
| # *args | ||||
| if func_code.co_flags & 0x04: | ||||
| name = arg_names[pos_count + keyword_only_count] | ||||
| annotation = annotations.get(name, _empty) | ||||
| parameters.append(Parameter(name, annotation=annotation, | ||||
| kind=_VAR_POSITIONAL)) | ||||
| # Keyword-only parameters. | ||||
| for name in keyword_only: | ||||
| default = _empty | ||||
| if kwdefaults is not None: | ||||
| default = kwdefaults.get(name, _empty) | ||||
| annotation = annotations.get(name, _empty) | ||||
| parameters.append(Parameter(name, annotation=annotation, | ||||
| kind=_KEYWORD_ONLY, | ||||
| default=default)) | ||||
| # **kwargs | ||||
| if func_code.co_flags & 0x08: | ||||
| index = pos_count + keyword_only_count | ||||
| if func_code.co_flags & 0x04: | ||||
| index += 1 | ||||
| name = arg_names[index] | ||||
| annotation = annotations.get(name, _empty) | ||||
| parameters.append(Parameter(name, annotation=annotation, | ||||
| kind=_VAR_KEYWORD)) | ||||
| return cls(parameters, | ||||
| return_annotation=annotations.get('return', _empty), | ||||
| __validate_parameters__=False) | ||||
| @property | ||||
| def parameters(self): | ||||
| try: | ||||
| return types.MappingProxyType(self._parameters) | ||||
| except AttributeError: | ||||
| return OrderedDict(self._parameters.items()) | ||||
| @property | ||||
| def return_annotation(self): | ||||
| return self._return_annotation | ||||
| def replace(self, parameters=_void, return_annotation=_void): | ||||
| '''Creates a customized copy of the Signature. | ||||
| Pass 'parameters' and/or 'return_annotation' arguments | ||||
| to override them in the new copy. | ||||
| ''' | ||||
| if parameters is _void: | ||||
| parameters = self.parameters.values() | ||||
| if return_annotation is _void: | ||||
| return_annotation = self._return_annotation | ||||
| return type(self)(parameters, | ||||
| return_annotation=return_annotation) | ||||
| def __hash__(self): | ||||
| msg = "unhashable type: '{0}'".format(self.__class__.__name__) | ||||
| raise TypeError(msg) | ||||
| def __eq__(self, other): | ||||
| if (not issubclass(type(other), Signature) or | ||||
| self.return_annotation != other.return_annotation or | ||||
| len(self.parameters) != len(other.parameters)): | ||||
| return False | ||||
| other_positions = dict((param, idx) | ||||
| for idx, param in enumerate(other.parameters.keys())) | ||||
| for idx, (param_name, param) in enumerate(self.parameters.items()): | ||||
| if param.kind == _KEYWORD_ONLY: | ||||
| try: | ||||
| other_param = other.parameters[param_name] | ||||
| except KeyError: | ||||
| return False | ||||
| else: | ||||
| if param != other_param: | ||||
| return False | ||||
| else: | ||||
| try: | ||||
| other_idx = other_positions[param_name] | ||||
| except KeyError: | ||||
| return False | ||||
| else: | ||||
| if (idx != other_idx or | ||||
| param != other.parameters[param_name]): | ||||
| return False | ||||
| return True | ||||
| def __ne__(self, other): | ||||
| return not self.__eq__(other) | ||||
| def _bind(self, args, kwargs, partial=False): | ||||
| '''Private method. Don't use directly.''' | ||||
| arguments = OrderedDict() | ||||
| parameters = iter(self.parameters.values()) | ||||
| parameters_ex = () | ||||
| arg_vals = iter(args) | ||||
| if partial: | ||||
| # Support for binding arguments to 'functools.partial' objects. | ||||
| # See 'functools.partial' case in 'signature()' implementation | ||||
| # for details. | ||||
| for param_name, param in self.parameters.items(): | ||||
| if (param._partial_kwarg and param_name not in kwargs): | ||||
| # Simulating 'functools.partial' behavior | ||||
| kwargs[param_name] = param.default | ||||
| while True: | ||||
| # Let's iterate through the positional arguments and corresponding | ||||
| # parameters | ||||
| try: | ||||
| arg_val = next(arg_vals) | ||||
| except StopIteration: | ||||
| # No more positional arguments | ||||
| try: | ||||
| param = next(parameters) | ||||
| except StopIteration: | ||||
| # No more parameters. That's it. Just need to check that | ||||
| # we have no `kwargs` after this while loop | ||||
| break | ||||
| else: | ||||
| if param.kind == _VAR_POSITIONAL: | ||||
| # That's OK, just empty *args. Let's start parsing | ||||
| # kwargs | ||||
| break | ||||
| elif param.name in kwargs: | ||||
| if param.kind == _POSITIONAL_ONLY: | ||||
| msg = '{arg!r} parameter is positional only, ' \ | ||||
| 'but was passed as a keyword' | ||||
| msg = msg.format(arg=param.name) | ||||
| raise TypeError(msg) | ||||
| parameters_ex = (param,) | ||||
| break | ||||
| elif (param.kind == _VAR_KEYWORD or | ||||
| param.default is not _empty): | ||||
| # That's fine too - we have a default value for this | ||||
| # parameter. So, lets start parsing `kwargs`, starting | ||||
| # with the current parameter | ||||
| parameters_ex = (param,) | ||||
| break | ||||
| else: | ||||
| if partial: | ||||
| parameters_ex = (param,) | ||||
| break | ||||
| else: | ||||
| msg = '{arg!r} parameter lacking default value' | ||||
| msg = msg.format(arg=param.name) | ||||
| raise TypeError(msg) | ||||
| else: | ||||
| # We have a positional argument to process | ||||
| try: | ||||
| param = next(parameters) | ||||
| except StopIteration: | ||||
| raise TypeError('too many positional arguments') | ||||
| else: | ||||
| if param.kind in (_VAR_KEYWORD, _KEYWORD_ONLY): | ||||
| # Looks like we have no parameter for this positional | ||||
| # argument | ||||
| raise TypeError('too many positional arguments') | ||||
| if param.kind == _VAR_POSITIONAL: | ||||
| # We have an '*args'-like argument, let's fill it with | ||||
| # all positional arguments we have left and move on to | ||||
| # the next phase | ||||
| values = [arg_val] | ||||
| values.extend(arg_vals) | ||||
| arguments[param.name] = tuple(values) | ||||
| break | ||||
| if param.name in kwargs: | ||||
| raise TypeError('multiple values for argument ' | ||||
| '{arg!r}'.format(arg=param.name)) | ||||
| arguments[param.name] = arg_val | ||||
| # Now, we iterate through the remaining parameters to process | ||||
| # keyword arguments | ||||
| kwargs_param = None | ||||
| for param in itertools.chain(parameters_ex, parameters): | ||||
| if param.kind == _POSITIONAL_ONLY: | ||||
| # This should never happen in case of a properly built | ||||
| # Signature object (but let's have this check here | ||||
| # to ensure correct behaviour just in case) | ||||
| raise TypeError('{arg!r} parameter is positional only, ' | ||||
| 'but was passed as a keyword'. \ | ||||
| format(arg=param.name)) | ||||
| if param.kind == _VAR_KEYWORD: | ||||
| # Memorize that we have a '**kwargs'-like parameter | ||||
| kwargs_param = param | ||||
| continue | ||||
| param_name = param.name | ||||
| try: | ||||
| arg_val = kwargs.pop(param_name) | ||||
| except KeyError: | ||||
| # We have no value for this parameter. It's fine though, | ||||
| # if it has a default value, or it is an '*args'-like | ||||
| # parameter, left alone by the processing of positional | ||||
| # arguments. | ||||
| if (not partial and param.kind != _VAR_POSITIONAL and | ||||
| param.default is _empty): | ||||
| raise TypeError('{arg!r} parameter lacking default value'. \ | ||||
| format(arg=param_name)) | ||||
| else: | ||||
| arguments[param_name] = arg_val | ||||
| if kwargs: | ||||
| if kwargs_param is not None: | ||||
| # Process our '**kwargs'-like parameter | ||||
| arguments[kwargs_param.name] = kwargs | ||||
| else: | ||||
| raise TypeError('too many keyword arguments') | ||||
| return self._bound_arguments_cls(self, arguments) | ||||
| def bind(self, *args, **kwargs): | ||||
| '''Get a BoundArguments object, that maps the passed `args` | ||||
| and `kwargs` to the function's signature. Raises `TypeError` | ||||
| if the passed arguments can not be bound. | ||||
| ''' | ||||
| return self._bind(args, kwargs) | ||||
| def bind_partial(self, *args, **kwargs): | ||||
| '''Get a BoundArguments object, that partially maps the | ||||
| passed `args` and `kwargs` to the function's signature. | ||||
| Raises `TypeError` if the passed arguments can not be bound. | ||||
| ''' | ||||
| return self._bind(args, kwargs, partial=True) | ||||
| def __str__(self): | ||||
| result = [] | ||||
| render_kw_only_separator = True | ||||
| for idx, param in enumerate(self.parameters.values()): | ||||
| formatted = str(param) | ||||
| kind = param.kind | ||||
| if kind == _VAR_POSITIONAL: | ||||
| # OK, we have an '*args'-like parameter, so we won't need | ||||
| # a '*' to separate keyword-only arguments | ||||
| render_kw_only_separator = False | ||||
| elif kind == _KEYWORD_ONLY and render_kw_only_separator: | ||||
| # We have a keyword-only parameter to render and we haven't | ||||
| # rendered an '*args'-like parameter before, so add a '*' | ||||
| # separator to the parameters list ("foo(arg1, *, arg2)" case) | ||||
| result.append('*') | ||||
| # This condition should be only triggered once, so | ||||
| # reset the flag | ||||
| render_kw_only_separator = False | ||||
| result.append(formatted) | ||||
| rendered = '({0})'.format(', '.join(result)) | ||||
| if self.return_annotation is not _empty: | ||||
| anno = formatannotation(self.return_annotation) | ||||
| rendered += ' -> {0}'.format(anno) | ||||
| return rendered | ||||