|
|
"""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 2.7 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):
|
|
|
if obj.__self__ is None:
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|
|
# Unbound method - treat it as a function (no distinction in Py 3)
|
|
|
obj = obj.__func__
|
|
|
else:
|
|
|
# Bound method: trim off the first parameter (typically 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 :meth:`Signature.bind` call. Holds the mapping of arguments
|
|
|
to the function's parameters.
|
|
|
|
|
|
Has the following public attributes:
|
|
|
|
|
|
arguments : :class:`collections.OrderedDict`
|
|
|
An ordered mutable mapping of parameters' names to arguments' values.
|
|
|
Does not contain arguments' default values.
|
|
|
signature : :class:`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:
|
|
|
|
|
|
parameters : :class:`collections.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
|
|
|
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.
|
|
|
'''
|
|
|
|
|
|
__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 :class:`BoundArguments` object, that maps the passed `args`
|
|
|
and `kwargs` to the function's signature. Raises :exc:`TypeError`
|
|
|
if the passed arguments can not be bound.
|
|
|
'''
|
|
|
return self._bind(args, kwargs)
|
|
|
|
|
|
def bind_partial(self, *args, **kwargs):
|
|
|
'''Get a :class:`BoundArguments` object, that partially maps the
|
|
|
passed `args` and `kwargs` to the function's signature.
|
|
|
Raises :exc:`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
|
|
|
|
