# -*- coding: utf-8 -*-
# Copyright (c) 2013, Mahmoud Hashemi
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following
# disclaimer in the documentation and/or other materials provided
# with the distribution.
#
# * The names of the contributors may not be used to endorse or
# promote products derived from this software without specific
# prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""Python's built-in :mod:`functools` module builds several useful
utilities on top of Python's first-class function
support. ``funcutils`` generally stays in the same vein, adding to and
correcting Python's standard metaprogramming facilities.
"""
from __future__ import print_function
import sys
import re
import inspect
import functools
import itertools
from types import MethodType, FunctionType
try:
xrange
make_method = MethodType
except NameError:
# Python 3
make_method = lambda desc, obj, obj_type: MethodType(desc, obj)
basestring = (str, bytes) # Python 3 compat
_IS_PY2 = False
else:
_IS_PY2 = True
try:
_inspect_iscoroutinefunction = inspect.iscoroutinefunction
except AttributeError:
# Python 3.4
_inspect_iscoroutinefunction = lambda func: False
try:
from .typeutils import make_sentinel
NO_DEFAULT = make_sentinel(var_name='NO_DEFAULT')
except ImportError:
NO_DEFAULT = object()
try:
from functools import partialmethod
except ImportError:
partialmethod = None
_IS_PY35 = sys.version_info >= (3, 5)
if not _IS_PY35:
# py35+ wants you to use signature instead, but
# inspect_formatargspec is way simpler for what it is. Copied the
# vendoring approach from alembic:
# https://github.com/sqlalchemy/alembic/blob/4cdad6aec32b4b5573a2009cc356cb4b144bd359/alembic/util/compat.py#L92
from inspect import formatargspec as inspect_formatargspec
else:
from inspect import formatannotation
def inspect_formatargspec(
args, varargs=None, varkw=None, defaults=None,
kwonlyargs=(), kwonlydefaults={}, annotations={},
formatarg=str,
formatvarargs=lambda name: '*' + name,
formatvarkw=lambda name: '**' + name,
formatvalue=lambda value: '=' + repr(value),
formatreturns=lambda text: ' -> ' + text,
formatannotation=formatannotation):
"""Copy formatargspec from python 3.7 standard library.
Python 3 has deprecated formatargspec and requested that Signature
be used instead, however this requires a full reimplementation
of formatargspec() in terms of creating Parameter objects and such.
Instead of introducing all the object-creation overhead and having
to reinvent from scratch, just copy their compatibility routine.
"""
def formatargandannotation(arg):
result = formatarg(arg)
if arg in annotations:
result += ': ' + formatannotation(annotations[arg])
return result
specs = []
if defaults:
firstdefault = len(args) - len(defaults)
for i, arg in enumerate(args):
spec = formatargandannotation(arg)
if defaults and i >= firstdefault:
spec = spec + formatvalue(defaults[i - firstdefault])
specs.append(spec)
if varargs is not None:
specs.append(formatvarargs(formatargandannotation(varargs)))
else:
if kwonlyargs:
specs.append('*')
if kwonlyargs:
for kwonlyarg in kwonlyargs:
spec = formatargandannotation(kwonlyarg)
if kwonlydefaults and kwonlyarg in kwonlydefaults:
spec += formatvalue(kwonlydefaults[kwonlyarg])
specs.append(spec)
if varkw is not None:
specs.append(formatvarkw(formatargandannotation(varkw)))
result = '(' + ', '.join(specs) + ')'
if 'return' in annotations:
result += formatreturns(formatannotation(annotations['return']))
return result
def get_module_callables(mod, ignore=None):
"""Returns two maps of (*types*, *funcs*) from *mod*, optionally
ignoring based on the :class:`bool` return value of the *ignore*
callable. *mod* can be a string name of a module in
:data:`sys.modules` or the module instance itself.
"""
if isinstance(mod, basestring):
mod = sys.modules[mod]
types, funcs = {}, {}
for attr_name in dir(mod):
if ignore and ignore(attr_name):
continue
try:
attr = getattr(mod, attr_name)
except Exception:
continue
try:
attr_mod_name = attr.__module__
except AttributeError:
continue
if attr_mod_name != mod.__name__:
continue
if isinstance(attr, type):
types[attr_name] = attr
elif callable(attr):
funcs[attr_name] = attr
return types, funcs
def mro_items(type_obj):
"""Takes a type and returns an iterator over all class variables
throughout the type hierarchy (respecting the MRO).
>>> sorted(set([k for k, v in mro_items(int) if not k.startswith('__') and 'bytes' not in k and not callable(v)]))
['denominator', 'imag', 'numerator', 'real']
"""
# TODO: handle slots?
return itertools.chain.from_iterable(ct.__dict__.items()
for ct in type_obj.__mro__)
def dir_dict(obj, raise_exc=False):
"""Return a dictionary of attribute names to values for a given
object. Unlike ``obj.__dict__``, this function returns all
attributes on the object, including ones on parent classes.
"""
# TODO: separate function for handling descriptors on types?
ret = {}
for k in dir(obj):
try:
ret[k] = getattr(obj, k)
except Exception:
if raise_exc:
raise
return ret
def copy_function(orig, copy_dict=True):
"""Returns a shallow copy of the function, including code object,
globals, closure, etc.
>>> func = lambda: func
>>> func() is func
True
>>> func_copy = copy_function(func)
>>> func_copy() is func
True
>>> func_copy is not func
True
Args:
orig (function): The function to be copied. Must be a
function, not just any method or callable.
copy_dict (bool): Also copy any attributes set on the function
instance. Defaults to ``True``.
"""
ret = FunctionType(orig.__code__,
orig.__globals__,
name=orig.__name__,
argdefs=getattr(orig, "__defaults__", None),
closure=getattr(orig, "__closure__", None))
if copy_dict:
ret.__dict__.update(orig.__dict__)
return ret
def partial_ordering(cls):
"""Class decorator, similar to :func:`functools.total_ordering`,
except it is used to define `partial orderings`_ (i.e., it is
possible that *x* is neither greater than, equal to, or less than
*y*). It assumes the presence of the ``__le__()`` and ``__ge__()``
method, but nothing else. It will not override any existing
additional comparison methods.
.. _partial orderings: https://en.wikipedia.org/wiki/Partially_ordered_set
>>> @partial_ordering
... class MySet(set):
... def __le__(self, other):
... return self.issubset(other)
... def __ge__(self, other):
... return self.issuperset(other)
...
>>> a = MySet([1,2,3])
>>> b = MySet([1,2])
>>> c = MySet([1,2,4])
>>> b < a
True
>>> b > a
False
>>> b < c
True
>>> a < c
False
>>> c > a
False
"""
def __lt__(self, other): return self <= other and not self >= other
def __gt__(self, other): return self >= other and not self <= other
def __eq__(self, other): return self >= other and self <= other
if not hasattr(cls, '__lt__'): cls.__lt__ = __lt__
if not hasattr(cls, '__gt__'): cls.__gt__ = __gt__
if not hasattr(cls, '__eq__'): cls.__eq__ = __eq__
return cls
class InstancePartial(functools.partial):
""":class:`functools.partial` is a huge convenience for anyone
working with Python's great first-class functions. It allows
developers to curry arguments and incrementally create simpler
callables for a variety of use cases.
Unfortunately there's one big gap in its usefulness:
methods. Partials just don't get bound as methods and
automatically handed a reference to ``self``. The
``InstancePartial`` type remedies this by inheriting from
:class:`functools.partial` and implementing the necessary
descriptor protocol. There are no other differences in
implementation or usage. :class:`CachedInstancePartial`, below,
has the same ability, but is slightly more efficient.
"""
if partialmethod is not None: # NB: See https://github.com/mahmoud/boltons/pull/244
@property
def _partialmethod(self):
return partialmethod(self.func, *self.args, **self.keywords)
def __get__(self, obj, obj_type):
return make_method(self, obj, obj_type)
class CachedInstancePartial(functools.partial):
"""The ``CachedInstancePartial`` is virtually the same as
:class:`InstancePartial`, adding support for method-usage to
:class:`functools.partial`, except that upon first access, it
caches the bound method on the associated object, speeding it up
for future accesses, and bringing the method call overhead to
about the same as non-``partial`` methods.
See the :class:`InstancePartial` docstring for more details.
"""
if partialmethod is not None: # NB: See https://github.com/mahmoud/boltons/pull/244
@property
def _partialmethod(self):
return partialmethod(self.func, *self.args, **self.keywords)
if sys.version_info >= (3, 6):
def __set_name__(self, obj_type, name):
self.__name__ = name
def __get__(self, obj, obj_type):
# These assignments could've been in __init__, but there was
# no simple way to do it without breaking one of PyPy or Py3.
self.__name__ = getattr(self, "__name__", None)
self.__doc__ = self.func.__doc__
self.__module__ = self.func.__module__
name = self.__name__
# if you're on python 3.6+, name will never be `None` bc `__set_name__` sets it when descriptor getting assigned
if name is None:
for k, v in mro_items(obj_type):
if v is self:
self.__name__ = name = k
if obj is None:
return make_method(self, obj, obj_type)
try:
# since this is a data descriptor, this block
# is probably only hit once (per object)
return obj.__dict__[name]
except KeyError:
obj.__dict__[name] = ret = make_method(self, obj, obj_type)
return ret
partial = CachedInstancePartial
def format_invocation(name='', args=(), kwargs=None, **kw):
"""Given a name, positional arguments, and keyword arguments, format
a basic Python-style function call.
>>> print(format_invocation('func', args=(1, 2), kwargs={'c': 3}))
func(1, 2, c=3)
>>> print(format_invocation('a_func', args=(1,)))
a_func(1)
>>> print(format_invocation('kw_func', kwargs=[('a', 1), ('b', 2)]))
kw_func(a=1, b=2)
"""
_repr = kw.pop('repr', repr)
if kw:
raise TypeError('unexpected keyword args: %r' % ', '.join(kw.keys()))
kwargs = kwargs or {}
a_text = ', '.join([_repr(a) for a in args])
if isinstance(kwargs, dict):
kwarg_items = [(k, kwargs[k]) for k in sorted(kwargs)]
else:
kwarg_items = kwargs
kw_text = ', '.join(['%s=%s' % (k, _repr(v)) for k, v in kwarg_items])
all_args_text = a_text
if all_args_text and kw_text:
all_args_text += ', '
all_args_text += kw_text
return '%s(%s)' % (name, all_args_text)
def format_exp_repr(obj, pos_names, req_names=None, opt_names=None, opt_key=None):
"""Render an expression-style repr of an object, based on attribute
names, which are assumed to line up with arguments to an initializer.
>>> class Flag(object):
... def __init__(self, length, width, depth=None):
... self.length = length
... self.width = width
... self.depth = depth
...
That's our Flag object, here are some example reprs for it:
>>> flag = Flag(5, 10)
>>> print(format_exp_repr(flag, ['length', 'width'], [], ['depth']))
Flag(5, 10)
>>> flag2 = Flag(5, 15, 2)
>>> print(format_exp_repr(flag2, ['length'], ['width', 'depth']))
Flag(5, width=15, depth=2)
By picking the pos_names, req_names, opt_names, and opt_key, you
can fine-tune how you want the repr to look.
Args:
obj (object): The object whose type name will be used and
attributes will be checked
pos_names (list): Required list of attribute names which will be
rendered as positional arguments in the output repr.
req_names (list): List of attribute names which will always
appear in the keyword arguments in the output repr. Defaults to None.
opt_names (list): List of attribute names which may appear in
the keyword arguments in the output repr, provided they pass
the *opt_key* check. Defaults to None.
opt_key (callable): A function or callable which checks whether
an opt_name should be in the repr. Defaults to a
``None``-check.
"""
cn = type(obj).__name__
req_names = req_names or []
opt_names = opt_names or []
uniq_names, all_names = set(), []
for name in req_names + opt_names:
if name in uniq_names:
continue
uniq_names.add(name)
all_names.append(name)
if opt_key is None:
opt_key = lambda v: v is None
assert callable(opt_key)
args = [getattr(obj, name, None) for name in pos_names]
kw_items = [(name, getattr(obj, name, None)) for name in all_names]
kw_items = [(name, val) for name, val in kw_items
if not (name in opt_names and opt_key(val))]
return format_invocation(cn, args, kw_items)
def format_nonexp_repr(obj, req_names=None, opt_names=None, opt_key=None):
"""Format a non-expression-style repr
Some object reprs look like object instantiation, e.g., App(r=[], mw=[]).
This makes sense for smaller, lower-level objects whose state
roundtrips. But a lot of objects contain values that don't
roundtrip, like types and functions.
For those objects, there is the non-expression style repr, which
mimic's Python's default style to make a repr like so:
>>> class Flag(object):
... def __init__(self, length, width, depth=None):
... self.length = length
... self.width = width
... self.depth = depth
...
>>> flag = Flag(5, 10)
>>> print(format_nonexp_repr(flag, ['length', 'width'], ['depth']))
<Flag length=5 width=10>
If no attributes are specified or set, utilizes the id, not unlike Python's
built-in behavior.
>>> print(format_nonexp_repr(flag))
<Flag id=...>
"""
cn = obj.__class__.__name__
req_names = req_names or []
opt_names = opt_names or []
uniq_names, all_names = set(), []
for name in req_names + opt_names:
if name in uniq_names:
continue
uniq_names.add(name)
all_names.append(name)
if opt_key is None:
opt_key = lambda v: v is None
assert callable(opt_key)
items = [(name, getattr(obj, name, None)) for name in all_names]
labels = ['%s=%r' % (name, val) for name, val in items
if not (name in opt_names and opt_key(val))]
if not labels:
labels = ['id=%s' % id(obj)]
ret = '<%s %s>' % (cn, ' '.join(labels))
return ret
# # #
# # # Function builder
# # #
def wraps(func, injected=None, expected=None, **kw):
"""Decorator factory to apply update_wrapper() to a wrapper function.
Modeled after built-in :func:`functools.wraps`. Returns a decorator
that invokes update_wrapper() with the decorated function as the wrapper
argument and the arguments to wraps() as the remaining arguments.
Default arguments are as for update_wrapper(). This is a convenience
function to simplify applying partial() to update_wrapper().
Same example as in update_wrapper's doc but with wraps:
>>> from boltons.funcutils import wraps
>>>
>>> def print_return(func):
... @wraps(func)
... def wrapper(*args, **kwargs):
... ret = func(*args, **kwargs)
... print(ret)
... return ret
... return wrapper
...
>>> @print_return
... def example():
... '''docstring'''
... return 'example return value'
>>>
>>> val = example()
example return value
>>> example.__name__
'example'
>>> example.__doc__
'docstring'
"""
return partial(update_wrapper, func=func, build_from=None,
injected=injected, expected=expected, **kw)
def update_wrapper(wrapper, func, injected=None, expected=None, build_from=None, **kw):
"""Modeled after the built-in :func:`functools.update_wrapper`,
this function is used to make your wrapper function reflect the
wrapped function's:
* Name
* Documentation
* Module
* Signature
The built-in :func:`functools.update_wrapper` copies the first three, but
does not copy the signature. This version of ``update_wrapper`` can copy
the inner function's signature exactly, allowing seamless usage
and :mod:`introspection <inspect>`. Usage is identical to the
built-in version::
>>> from boltons.funcutils import update_wrapper
>>>
>>> def print_return(func):
... def wrapper(*args, **kwargs):
... ret = func(*args, **kwargs)
... print(ret)
... return ret
... return update_wrapper(wrapper, func)
...
>>> @print_return
... def example():
... '''docstring'''
... return 'example return value'
>>>
>>> val = example()
example return value
>>> example.__name__
'example'
>>> example.__doc__
'docstring'
In addition, the boltons version of update_wrapper supports
modifying the outer signature. By passing a list of
*injected* argument names, those arguments will be removed from
the outer wrapper's signature, allowing your decorator to provide
arguments that aren't passed in.
Args:
wrapper (function) : The callable to which the attributes of
*func* are to be copied.
func (function): The callable whose attributes are to be copied.
injected (list): An optional list of argument names which
should not appear in the new wrapper's signature.
expected (list): An optional list of argument names (or (name,
default) pairs) representing new arguments introduced by
the wrapper (the opposite of *injected*). See
:meth:`FunctionBuilder.add_arg()` for more details.
build_from (function): The callable from which the new wrapper
is built. Defaults to *func*, unless *wrapper* is partial object
built from *func*, in which case it defaults to *wrapper*.
Useful in some specific cases where *wrapper* and *func* have the
same arguments but differ on which are keyword-only and positional-only.
update_dict (bool): Whether to copy other, non-standard
attributes of *func* over to the wrapper. Defaults to True.
inject_to_varkw (bool): Ignore missing arguments when a
``**kwargs``-type catch-all is present. Defaults to True.
hide_wrapped (bool): Remove reference to the wrapped function(s)
in the updated function.
In opposition to the built-in :func:`functools.update_wrapper` bolton's
version returns a copy of the function and does not modify anything in place.
For more in-depth wrapping of functions, see the
:class:`FunctionBuilder` type, on which update_wrapper was built.
"""
if injected is None:
injected = []
elif isinstance(injected, basestring):
injected = [injected]
else:
injected = list(injected)
expected_items = _parse_wraps_expected(expected)
if isinstance(func, (classmethod, staticmethod)):
raise TypeError('wraps does not support wrapping classmethods and'
' staticmethods, change the order of wrapping to'
' wrap the underlying function: %r'
% (getattr(func, '__func__', None),))
update_dict = kw.pop('update_dict', True)
inject_to_varkw = kw.pop('inject_to_varkw', True)
hide_wrapped = kw.pop('hide_wrapped', False)
if kw:
raise TypeError('unexpected kwargs: %r' % kw.keys())
if isinstance(wrapper, functools.partial) and func is wrapper.func:
build_from = build_from or wrapper
fb = FunctionBuilder.from_func(build_from or func)
for arg in injected:
try:
fb.remove_arg(arg)
except MissingArgument:
if inject_to_varkw and fb.varkw is not None:
continue # keyword arg will be caught by the varkw
raise
for arg, default in expected_items:
fb.add_arg(arg, default) # may raise ExistingArgument
if fb.is_async:
fb.body = 'return await _call(%s)' % fb.get_invocation_str()
else:
fb.body = 'return _call(%s)' % fb.get_invocation_str()
execdict = dict(_call=wrapper, _func=func)
fully_wrapped = fb.get_func(execdict, with_dict=update_dict)
if hide_wrapped and hasattr(fully_wrapped, '__wrapped__'):
del fully_wrapped.__dict__['__wrapped__']
elif not hide_wrapped:
fully_wrapped.__wrapped__ = func # ref to the original function (#115)
return fully_wrapped
def _parse_wraps_expected(expected):
# expected takes a pretty powerful argument, it's processed
# here. admittedly this would be less trouble if I relied on
# OrderedDict (there's an impl of that in the commit history if
# you look
if expected is None:
expected = []
elif isinstance(expected, basestring):
expected = [(expected, NO_DEFAULT)]
expected_items = []
try:
expected_iter = iter(expected)
except TypeError as e:
raise ValueError('"expected" takes string name, sequence of string names,'
' iterable of (name, default) pairs, or a mapping of '
' {name: default}, not %r (got: %r)' % (expected, e))
for argname in expected_iter:
if isinstance(argname, basestring):
# dict keys and bare strings
try:
default = expected[argname]
except TypeError:
default = NO_DEFAULT
else:
# pairs
try:
argname, default = argname
except (TypeError, ValueError):
raise ValueError('"expected" takes string name, sequence of string names,'
' iterable of (name, default) pairs, or a mapping of '
' {name: default}, not %r')
if not isinstance(argname, basestring):
raise ValueError('all "expected" argnames must be strings, not %r' % (argname,))
expected_items.append((argname, default))
return expected_items
class FunctionBuilder(object):
"""The FunctionBuilder type provides an interface for programmatically
creating new functions, either based on existing functions or from
scratch.
Values are passed in at construction or set as attributes on the
instance. For creating a new function based of an existing one,
see the :meth:`~FunctionBuilder.from_func` classmethod. At any
point, :meth:`~FunctionBuilder.get_func` can be called to get a
newly compiled function, based on the values configured.
>>> fb = FunctionBuilder('return_five', doc='returns the integer 5',
... body='return 5')
>>> f = fb.get_func()
>>> f()
5
>>> fb.varkw = 'kw'
>>> f_kw = fb.get_func()
>>> f_kw(ignored_arg='ignored_val')
5
Note that function signatures themselves changed quite a bit in
Python 3, so several arguments are only applicable to
FunctionBuilder in Python 3. Except for *name*, all arguments to
the constructor are keyword arguments.
Args:
name (str): Name of the function.
doc (str): `Docstring`_ for the function, defaults to empty.
module (str): Name of the module from which this function was
imported. Defaults to None.
body (str): String version of the code representing the body
of the function. Defaults to ``'pass'``, which will result
in a function which does nothing and returns ``None``.
args (list): List of argument names, defaults to empty list,
denoting no arguments.
varargs (str): Name of the catch-all variable for positional
arguments. E.g., "args" if the resultant function is to have
``*args`` in the signature. Defaults to None.
varkw (str): Name of the catch-all variable for keyword
arguments. E.g., "kwargs" if the resultant function is to have
``**kwargs`` in the signature. Defaults to None.
defaults (tuple): A tuple containing default argument values for
those arguments that have defaults.
kwonlyargs (list): Argument names which are only valid as
keyword arguments. **Python 3 only.**
kwonlydefaults (dict): A mapping, same as normal *defaults*,
but only for the *kwonlyargs*. **Python 3 only.**
annotations (dict): Mapping of type hints and so
forth. **Python 3 only.**
filename (str): The filename that will appear in
tracebacks. Defaults to "boltons.funcutils.FunctionBuilder".
indent (int): Number of spaces with which to indent the
function *body*. Values less than 1 will result in an error.
dict (dict): Any other attributes which should be added to the
functions compiled with this FunctionBuilder.
All of these arguments are also made available as attributes which
can be mutated as necessary.
.. _Docstring: https://en.wikipedia.org/wiki/Docstring#Python
"""
if _IS_PY2:
_argspec_defaults = {'args': list,
'varargs': lambda: None,
'varkw': lambda: None,
'defaults': lambda: None}
@classmethod
def _argspec_to_dict(cls, f):
args, varargs, varkw, defaults = inspect.getargspec(f)
return {'args': args,
'varargs': varargs,
'varkw': varkw,
'defaults': defaults}
else:
_argspec_defaults = {'args': list,
'varargs': lambda: None,
'varkw': lambda: None,
'defaults': lambda: None,
'kwonlyargs': list,
'kwonlydefaults': dict,
'annotations': dict}
@classmethod
def _argspec_to_dict(cls, f):
argspec = inspect.getfullargspec(f)
return dict((attr, getattr(argspec, attr))
for attr in cls._argspec_defaults)
_defaults = {'doc': str,
'dict': dict,
'is_async': lambda: False,
'module': lambda: None,
'body': lambda: 'pass',
'indent': lambda: 4,
"annotations": dict,
'filename': lambda: 'boltons.funcutils.FunctionBuilder'}
_defaults.update(_argspec_defaults)
_compile_count = itertools.count()
def __init__(self, name, **kw):
self.name = name
for a, default_factory in self._defaults.items():
val = kw.pop(a, None)
if val is None:
val = default_factory()
setattr(self, a, val)
if kw:
raise TypeError('unexpected kwargs: %r' % kw.keys())
return
# def get_argspec(self): # TODO
if _IS_PY2:
def get_sig_str(self, with_annotations=True):
"""Return function signature as a string.
with_annotations is ignored on Python 2. On Python 3 signature
will omit annotations if it is set to False.
"""
return inspect_formatargspec(self.args, self.varargs,
self.varkw, [])
def get_invocation_str(self):
return inspect_formatargspec(self.args, self.varargs,
self.varkw, [])[1:-1]
else:
def get_sig_str(self, with_annotations=True):
"""Return function signature as a string.
with_annotations is ignored on Python 2. On Python 3 signature
will omit annotations if it is set to False.
"""
if with_annotations:
annotations = self.annotations
else:
annotations = {}
return inspect_formatargspec(self.args,
self.varargs,
self.varkw,
[],
self.kwonlyargs,
{},
annotations)
_KWONLY_MARKER = re.compile(r"""
\* # a star
\s* # followed by any amount of whitespace
, # followed by a comma
\s* # followed by any amount of whitespace
""", re.VERBOSE)
def get_invocation_str(self):
kwonly_pairs = None
formatters = {}
if self.kwonlyargs:
kwonly_pairs = dict((arg, arg)
for arg in self.kwonlyargs)
formatters['formatvalue'] = lambda value: '=' + value
sig = inspect_formatargspec(self.args,
self.varargs,
self.varkw,
[],
kwonly_pairs,
kwonly_pairs,
{},
**formatters)
sig = self._KWONLY_MARKER.sub('', sig)
return sig[1:-1]
@classmethod
def from_func(cls, func):
"""Create a new FunctionBuilder instance based on an existing
function. The original function will not be stored or
modified.
"""
# TODO: copy_body? gonna need a good signature regex.
# TODO: might worry about __closure__?
if not callable(func):
raise TypeError('expected callable object, not %r' % (func,))
if isinstance(func, functools.partial):
if _IS_PY2:
raise ValueError('Cannot build FunctionBuilder instances from partials in python 2.')
kwargs = {'name': func.func.__name__,
'doc': func.func.__doc__,
'module': getattr(func.func, '__module__', None), # e.g., method_descriptor
'annotations': getattr(func.func, "__annotations__", {}),
'dict': getattr(func.func, '__dict__', {})}
else:
kwargs = {'name': func.__name__,
'doc': func.__doc__,
'module': getattr(func, '__module__', None), # e.g., method_descriptor
'annotations': getattr(func, "__annotations__", {}),
'dict': getattr(func, '__dict__', {})}
kwargs.update(cls._argspec_to_dict(func))
if _inspect_iscoroutinefunction(func):
kwargs['is_async'] = True
return cls(**kwargs)
def get_func(self, execdict=None, add_source=True, with_dict=True):
"""Compile and return a new function based on the current values of
the FunctionBuilder.
Args:
execdict (dict): The dictionary representing the scope in
which the compilation should take place. Defaults to an empty
dict.
add_source (bool): Whether to add the source used to a
special ``__source__`` attribute on the resulting
function. Defaults to True.
with_dict (bool): Add any custom attributes, if
applicable. Defaults to True.
To see an example of usage, see the implementation of
:func:`~boltons.funcutils.wraps`.
"""
execdict = execdict or {}
body = self.body or self._default_body
tmpl = 'def {name}{sig_str}:'
tmpl += '\n{body}'
if self.is_async:
tmpl = 'async ' + tmpl
body = _indent(self.body, ' ' * self.indent)
name = self.name.replace('<', '_').replace('>', '_') # lambdas
src = tmpl.format(name=name, sig_str=self.get_sig_str(with_annotations=False),
doc=self.doc, body=body)
self._compile(src, execdict)
func = execdict[name]
func.__name__ = self.name
func.__doc__ = self.doc
func.__defaults__ = self.defaults
if not _IS_PY2:
func.__kwdefaults__ = self.kwonlydefaults
func.__annotations__ = self.annotations
if with_dict:
func.__dict__.update(self.dict)
func.__module__ = self.module
# TODO: caller module fallback?
if add_source:
func.__source__ = src
return func
def get_defaults_dict(self):
"""Get a dictionary of function arguments with defaults and the
respective values.
"""
ret = dict(reversed(list(zip(reversed(self.args),
reversed(self.defaults or [])))))
kwonlydefaults = getattr(self, 'kwonlydefaults', None)
if kwonlydefaults:
ret.update(kwonlydefaults)
return ret
def get_arg_names(self, only_required=False):
arg_names = tuple(self.args) + tuple(getattr(self, 'kwonlyargs', ()))
if only_required:
defaults_dict = self.get_defaults_dict()
arg_names = tuple([an for an in arg_names if an not in defaults_dict])
return arg_names
if _IS_PY2:
def add_arg(self, arg_name, default=NO_DEFAULT):
"Add an argument with optional *default* (defaults to ``funcutils.NO_DEFAULT``)."
if arg_name in self.args:
raise ExistingArgument('arg %r already in func %s arg list' % (arg_name, self.name))
self.args.append(arg_name)
if default is not NO_DEFAULT:
self.defaults = (self.defaults or ()) + (default,)
return
else:
def add_arg(self, arg_name, default=NO_DEFAULT, kwonly=False):
"""Add an argument with optional *default* (defaults to
``funcutils.NO_DEFAULT``). Pass *kwonly=True* to add a
keyword-only argument
"""
if arg_name in self.args:
raise ExistingArgument('arg %r already in func %s arg list' % (arg_name, self.name))
if arg_name in self.kwonlyargs:
raise ExistingArgument('arg %r already in func %s kwonly arg list' % (arg_name, self.name))
if not kwonly:
self.args.append(arg_name)
if default is not NO_DEFAULT:
self.defaults = (self.defaults or ()) + (default,)
else:
self.kwonlyargs.append(arg_name)
if default is not NO_DEFAULT:
self.kwonlydefaults[arg_name] = default
return
def remove_arg(self, arg_name):
"""Remove an argument from this FunctionBuilder's argument list. The
resulting function will have one less argument per call to
this function.
Args:
arg_name (str): The name of the argument to remove.
Raises a :exc:`ValueError` if the argument is not present.
"""
args = self.args
d_dict = self.get_defaults_dict()
try:
args.remove(arg_name)
except ValueError:
try:
self.kwonlyargs.remove(arg_name)
except (AttributeError, ValueError):
# py2, or py3 and missing from both
exc = MissingArgument('arg %r not found in %s argument list:'
' %r' % (arg_name, self.name, args))
exc.arg_name = arg_name
raise exc
else:
self.kwonlydefaults.pop(arg_name, None)
else:
d_dict.pop(arg_name, None)
self.defaults = tuple([d_dict[a] for a in args if a in d_dict])
return
def _compile(self, src, execdict):
filename = ('<%s-%d>'
% (self.filename, next(self._compile_count),))
try:
code = compile(src, filename, 'single')
exec(code, execdict)
except Exception:
raise
return execdict
class MissingArgument(ValueError):
pass
class ExistingArgument(ValueError):
pass
def _indent(text, margin, newline='\n', key=bool):
"based on boltons.strutils.indent"
indented_lines = [(margin + line if key(line) else line)
for line in text.splitlines()]
return newline.join(indented_lines)
try:
from functools import total_ordering # 2.7+
except ImportError:
# python 2.6
def total_ordering(cls):
"""Class decorator that fills in missing comparators/ordering
methods. Backport of :func:`functools.total_ordering` to work
with Python 2.6.
Code from http://code.activestate.com/recipes/576685/
"""
convert = {
'__lt__': [
('__gt__',
lambda self, other: not (self < other or self == other)),
('__le__',
lambda self, other: self < other or self == other),
('__ge__',
lambda self, other: not self < other)],
'__le__': [
('__ge__',
lambda self, other: not self <= other or self == other),
('__lt__',
lambda self, other: self <= other and not self == other),
('__gt__',
lambda self, other: not self <= other)],
'__gt__': [
('__lt__',
lambda self, other: not (self > other or self == other)),
('__ge__',
lambda self, other: self > other or self == other),
('__le__',
lambda self, other: not self > other)],
'__ge__': [
('__le__',
lambda self, other: (not self >= other) or self == other),
('__gt__',
lambda self, other: self >= other and not self == other),
('__lt__',
lambda self, other: not self >= other)]
}
roots = set(dir(cls)) & set(convert)
if not roots:
raise ValueError('must define at least one ordering operation:'
' < > <= >=')
root = max(roots) # prefer __lt__ to __le__ to __gt__ to __ge__
for opname, opfunc in convert[root]:
if opname not in roots:
opfunc.__name__ = opname
opfunc.__doc__ = getattr(int, opname).__doc__
setattr(cls, opname, opfunc)
return cls
def noop(*args, **kwargs):
"""
Simple function that should be used when no effect is desired.
An alternative to checking for an optional function type parameter.
e.g.
def decorate(func, pre_func=None, post_func=None):
if pre_func:
pre_func()
func()
if post_func:
post_func()
vs
def decorate(func, pre_func=noop, post_func=noop):
pre_func()
func()
post_func()
"""
return None
# end funcutils.py