def encode_coerce(arg):
"""Encode string objects."""
import locale
from . import Invalid
from xoutil.eight import callable
encoding = locale.getpreferredencoding() or "UTF-8"
encode = getattr(arg, "encode", None)
if callable(encode):
try:
res = encode(encoding, "replace")
if not isinstance(res, bytes):
res = None
except BaseException:
res = None
else:
res = None
if res is None:
try:
import codecs
res = codecs.encode(arg, encoding, "replace")
except BaseException:
res = Invalid
return res
def decode_coerce(arg):
"""Decode objects implementing the buffer protocol."""
import locale
from . import Invalid
from xoutil.eight import text_type, callable
encoding = locale.getpreferredencoding() or "UTF-8"
decode = getattr(arg, "decode", None)
if callable(decode):
try:
res = decode(encoding, "replace")
if not isinstance(res, text_type):
res = None
except BaseException:
res = None
else:
res = None
if res is None:
try:
# TODO: All arrays are decoded, and not only those containing
# valid byte or unicode characters.
import codecs
res = codecs.decode(arg, encoding, "replace")
except BaseException:
res = Invalid
return res
def fix_class_documentation(cls, ignore=None, min_length=10, deep=1,
default=None):
'''Fix the documentation for the given class using its super-classes.
This function may be useful for shells or Python Command Line Interfaces
(CLI).
If `cls` has an invalid documentation, super-classes are recursed
in MRO until a documentation definition was made at any level.
:param ignore: could be used to specify which classes to ignore by
specifying its name in this list.
:param min_length: specify that documentations with less that a number of
characters, also are ignored.
'''
assert isinstance(cls, type), _INVALID_CLASS_TYPE_MSG
if _len(cls.__doc__) < min_length:
ignore = ignore or ()
def get_doc(c):
if (c.__name__ not in ignore) and _len(c.__doc__) >= min_length:
return c.__doc__
else:
return None
doc = build_documentation(cls, get_doc, deep)
if doc:
cls.__doc__ = doc
elif default:
cls.__doc__ = default(cls) if callable(default) else default
def valid(chk, stack=True):
if isinstance(chk, (bool, Logical)):
res = bool(chk)
elif isinstance(chk, type):
res = isinstance(obj, chk)
elif isinstance(chk, tuple):
if not chk:
res = False
elif all(isinstance(c, type) for c in chk):
res = isinstance(obj, chk)
else:
res = any(valid(c, stack=False) for c in chk)
elif isinstance(chk, list):
res = all(valid(c) for c in chk)
elif isinstance(chk, Set):
res = obj in chk
elif isinstance(chk, Mapping):
res = chk.get(obj, False)
elif callable(chk):
res = chk(obj)
else:
res = False
if not res and stack:
self.failed_stack.append(chk)
return res
def power(*args):
'''Returns the "power" composition of several functions.
Examples::
>>> import operator
>>> f = power(partial(operator.mul, 3), 3)
>>> f(23) == 3*(3*(3*23))
True
>>> power(operator.neg)
Traceback (most recent call last):
...
TypeError: Function `power` requires at least two arguments
'''
try:
funcs, times = args[:-1], args[-1]
except IndexError:
msg = "Function `power` requires at least two arguments"
raise TypeError(msg)
if not funcs:
raise TypeError('Function `power` requires at least two arguments')
if any(not callable(func) for func in funcs):
raise TypeError('First arguments of `power` must be callables')
if not isinstance(times, int):
raise TypeError('Last argument of `power` must be int')
if len(funcs) > 1:
base = (compose(funcs), )
else:
base = (funcs[0], )
return compose(*(base * times))
def is_file_like(obj):
'''Return if `obj` is a valid file type or not.'''
from xoutil.eight import _py2, callable
types = (file, IOBase) if _py2 else (IOBase, )
if isinstance(obj, types):
return True
else:
methods = ('close', 'write', 'read')
return all(callable(getattr(obj, name, None)) for name in methods)
def get_doc(c):
if (c.__name__ not in ignore):
method = c.__dict__.get(method_name)
if callable(method) and _len(method.__doc__) >= min_length:
return method.__doc__
else:
return None
else:
return None
def __parse_arguments(self, *args, **kwargs):
'''Assign parsed arguments to the just created instance.'''
from xoutil.validators import (is_valid_identifier, predicate)
self.attr_name = Unset
self.init = Unset
self.default = Unset
self.do_assigning = True
self.validator = True
for i, arg in enumerate(args):
if self.attr_name is Unset and is_valid_identifier(arg):
self.attr_name = arg
elif self.init is Unset and callable(arg):
self.init = arg
else:
msg = ('Invalid positional arguments: %s at %s\n'
'Valid arguments are the attribute name and a '
'callable constructor for initial value.')
raise ValueError(msg % (args[i:], i))
bads = {}
for key in kwargs:
value = kwargs[key]
if (self.default is Unset and self.init is Unset and
key in ('default', 'value', 'initial_value')):
self.default = value
elif (self.validator is True and
key in ('validator', 'checker', 'check')):
self.validator = value
elif (self.do_assigning is True and key == 'do_assigning' and
value is False):
self.do_assigning = False
else:
bads[key] = value
self.validator = predicate(self.validator)
if bads:
msg = ('Invalid keyword arguments: %s\n'
'See constructor documentation for more info.')
raise ValueError(msg % bads)
if self.attr_name is Unset:
from xoutil.names import nameof
if self.init is not Unset:
if isinstance(self.init, type):
self.attr_name = str('_%s' % self.init.__name__)
else:
self.attr_name = nameof(self.init, safe=True)
else:
self.attr_name = self._unique_name()
self.inner_name = str('__%s__' % self.attr_name.strip('_'))
def get_method_function(cls, method_name):
'''Get definition function given in its `method_name`.
There is a difference between the result of this function and
``getattr(cls, method_name)`` because the last one return the unbound
method and this a python function.
'''
if not isinstance(cls, type):
cls = cls.__class__
mro = cls.mro()
i, res = 0, None
while not res and (i < len(mro)):
sc = mro[i]
method = sc.__dict__.get(method_name)
if callable(method):
res = method
else:
i += 1
return res
def compose(*callables, **kwargs):
'''Returns a function that is the composition of several `callables`.
By default `compose` behaves like mathematical function composition: this
is to say that ``compose(f1, ... fn)`` is equivalent to ``lambda _x:
fn(...(f1(_x))...)``.
If any "intermediate" function returns a :class:`ctuple` it is expanded as
several positional arguments to the next function.
.. versionchanged:: 1.5.5 At least a callable must be passed, otherwise a
TypeError is raised. If a single callable is passed
it is returned without change.
:param math: Indicates if `compose` should behave like mathematical
function composition: last function in `funcs` is applied
last. If False, then the last function in `func` is applied
first.
'''
if not callables:
raise TypeError('At least a function must be provided')
if not all(callable(func) for func in callables):
raise TypeError('Every func must a callable')
if len(callables) == 1:
return callables[0]
math = kwargs.get('math', True)
if not math:
callables = list(reversed(callables))
def _inner(*args):
f, functions = callables[0], callables[1:]
result = f(*args)
for f in functions:
if isinstance(result, ctuple):
result = f(*result)
else:
result = f(result)
return result
return _inner
def __call__(self):
res = self.value
if callable(res):
return res(*self.args, **self.kwargs)
else:
return res
def smart_copy(*args, **kwargs):
'''Copies the first apparition of attributes (or keys) from `sources` to
`target`.
:param sources: The objects from which to extract keys or attributes.
:param target: The object to fill.
:param defaults: Default values for the attributes to be copied as
explained below. Defaults to False.
:type defaults: Either a bool, a dictionary, an iterable or a callable.
Every `sources` and `target` are always positional arguments. There should
be at least one source. `target` will always be the last positional
argument.
If `defaults` is a dictionary or an iterable then only the names provided
by itering over `defaults` will be copied. If `defaults` is a dictionary,
and one of its key is not found in any of the `sources`, then the value of
the key in the dictionary is copied to `target` unless:
- It's the value :class:`xoutil.types.Required` or an instance of Required.
- An exception object
- A sequence with is first value being a subclass of Exception. In which
case :class:`xoutil.data.adapt_exception` is used.
In these cases a KeyError is raised if the key is not found in the
sources.
If `default` is an iterable and a key is not found in any of the sources,
None is copied to `target`.
If `defaults` is a callable then it should receive one positional
arguments for the current `attribute name` and several keyword arguments
(we pass ``source``) and return either True or False if the attribute
should be copied.
If `defaults` is False (or None) only the attributes that do not start
with a "_" are copied, if it's True all attributes are copied.
When `target` is not a mapping only valid Python identifiers will be
copied.
Each `source` is considered a mapping if it's an instance of
`collections.Mapping` or a `MappingProxyType`.
The `target` is considered a mapping if it's an instance of
`collections.MutableMapping`.
:returns: `target`.
.. versionchanged:: 1.7.0 `defaults` is now keyword only.
'''
from collections import MutableMapping
from xoutil.types import is_collection, is_mapping, Required
from xoutil.data import adapt_exception
from xoutil.validators.identifiers import is_valid_identifier
defaults = kwargs.pop('defaults', False)
if kwargs:
raise TypeError('smart_copy does not accept a "%s" keyword argument'
% kwargs.keys()[0])
sources, target = args[:-1], args[-1]
if not sources:
raise TypeError('smart_copy requires at least one source')
if isinstance(target, (bool, type(None), int, float, str_base)):
raise TypeError('target should be a mutable object, not %s' %
type(target))
if isinstance(target, MutableMapping):
def setter(key, val):
target[key] = val
else:
def setter(key, val):
if is_valid_identifier(key):
setattr(target, key, val)
_mapping = is_mapping(defaults)
if _mapping or is_collection(defaults):
for key, val in ((key, get_first_of(sources, key, default=Unset))
for key in defaults):
if val is Unset:
if _mapping:
val = defaults.get(key, None)
else:
val = None
exc = adapt_exception(val, key=key)
if exc or val is Required or isinstance(val, Required):
raise KeyError(key)
setter(key, val)
else:
keys = []
for source in sources:
get = smart_getter(source)
if is_mapping(source):
items = (name for name in source)
else:
items = dir(source)
for key in items:
private = isinstance(key, str_base) and key.startswith('_')
if (defaults is False or defaults is None) and private:
copy = False
elif callable(defaults):
copy = defaults(key, source=source)
else:
copy = True
if key not in keys:
keys.append(key)
if copy:
setter(key, get(key))
return target
def _get_ignored(what):
if callable(what):
return what
else:
return lambda s: s == what
def _get_checker_name(checker, full=False):
'''Return a nice name for a `checker`.
:param full: If True, return a detailed representation of the checker.
See :class:`Predicate` for possible checker kinds.
'''
from xoutil.logical import Logical
from xoutil.collections import Set, Mapping, PascalSet
from xoutil.eight import callable
from xoutil.inspect import type_name
from xoutil.string import safe_str as sstr # , safe_repr as srepr
srepr = repr
if isinstance(checker, (bool, Logical)):
return str(checker)
elif isinstance(checker, Predicate):
return str('p(%s)') % checker.get_name()
elif isinstance(checker, type):
return type_name(checker, affirm=True)
elif isinstance(checker, list):
if not checker:
return str(True)
else:
return str(' & ').join(_get_checker_name(c) for c in checker)
elif isinstance(checker, tuple):
if not checker:
return str(False)
elif all(isinstance(c, type) for c in checker):
return type_name(checker, affirm=True)
else:
res = str(' | ').join(_get_checker_name(c) for c in checker)
return str('(%s)' % res)
elif isinstance(checker, PascalSet):
return str(checker)
elif isinstance(checker, Set):
if checker:
aux = srepr(next(iter(checker)))
if len(checker) > 1:
aux += str(', ...')
else:
aux = str()
return str('{%s}') % aux
elif isinstance(checker, Mapping):
if checker:
key = next(iter(checker))
aux = str('%s: %s') % (srepr(key), srepr(checker[key]))
if len(checker) > 1:
aux += str(', ...')
else:
aux = str()
return str('{%s}') % aux
elif callable(checker):
res = type_name(checker, affirm=True)
if 'lambda' in res:
from inspect import getargspec
res = res.replace('<lambda>', '<λ>')
args = getargspec(checker).args
res = sstr('%s(%s)' % (res, ', '.join(args)))
return res
else:
return str('False(%)' % srepr(checker))
def callable_coerce(arg):
"""Check if `arg` is a callable object."""
from xoutil.eight import callable
return arg if callable(arg) else Invalid
