# AUTOGENERATED! DO NOT EDIT! File to edit: ../nbs/07_meta.ipynb.
# %% auto 0
__all__ = ['test_sig', 'FixSigMeta', 'PrePostInitMeta', 'AutoInit', 'NewChkMeta', 'BypassNewMeta', 'empty2none', 'anno_dict',
'use_kwargs_dict', 'use_kwargs', 'delegates', 'method', 'funcs_kwargs']
# %% ../nbs/07_meta.ipynb 1
from .imports import *
from .test import *
from contextlib import contextmanager
from copy import copy
import inspect
# %% ../nbs/07_meta.ipynb 5
def test_sig(f, b):
"Test the signature of an object"
test_eq(str(inspect.signature(f)), b)
# %% ../nbs/07_meta.ipynb 7
def _rm_self(sig):
sigd = dict(sig.parameters)
sigd.pop('self')
return sig.replace(parameters=sigd.values())
# %% ../nbs/07_meta.ipynb 8
class FixSigMeta(type):
"A metaclass that fixes the signature on classes that override `__new__`"
def __new__(cls, name, bases, dict):
res = super().__new__(cls, name, bases, dict)
if res.__init__ is not object.__init__: res.__signature__ = _rm_self(inspect.signature(res.__init__))
return res
# %% ../nbs/07_meta.ipynb 23
class PrePostInitMeta(FixSigMeta):
"A metaclass that calls optional `__pre_init__` and `__post_init__` methods"
def __call__(cls, *args, **kwargs):
res = cls.__new__(cls)
if type(res)==cls:
if hasattr(res,'__pre_init__'): res.__pre_init__(*args,**kwargs)
res.__init__(*args,**kwargs)
if hasattr(res,'__post_init__'): res.__post_init__(*args,**kwargs)
return res
# %% ../nbs/07_meta.ipynb 28
class AutoInit(metaclass=PrePostInitMeta):
"Same as `object`, but no need for subclasses to call `super().__init__`"
def __pre_init__(self, *args, **kwargs): super().__init__(*args, **kwargs)
# %% ../nbs/07_meta.ipynb 31
class NewChkMeta(FixSigMeta):
"Metaclass to avoid recreating object passed to constructor"
def __call__(cls, x=None, *args, **kwargs):
if not args and not kwargs and x is not None and isinstance(x,cls): return x
res = super().__call__(*((x,) + args), **kwargs)
return res
# %% ../nbs/07_meta.ipynb 44
class BypassNewMeta(FixSigMeta):
"Metaclass: casts `x` to this class if it's of type `cls._bypass_type`"
def __call__(cls, x=None, *args, **kwargs):
if hasattr(cls, '_new_meta'): x = cls._new_meta(x, *args, **kwargs)
elif not isinstance(x,getattr(cls,'_bypass_type',object)) or len(args) or len(kwargs):
x = super().__call__(*((x,)+args), **kwargs)
if cls!=x.__class__: x.__class__ = cls
return x
# %% ../nbs/07_meta.ipynb 54
def empty2none(p):
"Replace `Parameter.empty` with `None`"
return None if p==inspect.Parameter.empty else p
# %% ../nbs/07_meta.ipynb 55
def anno_dict(f):
"`__annotation__ dictionary with `empty` cast to `None`, returning empty if doesn't exist"
return {k:empty2none(v) for k,v in getattr(f, '__annotations__', {}).items()}
# %% ../nbs/07_meta.ipynb 57
def _mk_param(n,d=None): return inspect.Parameter(n, inspect.Parameter.KEYWORD_ONLY, default=d)
# %% ../nbs/07_meta.ipynb 58
def use_kwargs_dict(keep=False, **kwargs):
"Decorator: replace `**kwargs` in signature with `names` params"
def _f(f):
sig = inspect.signature(f)
sigd = dict(sig.parameters)
k = sigd.pop('kwargs')
s2 = {n:_mk_param(n,d) for n,d in kwargs.items() if n not in sigd}
sigd.update(s2)
if keep: sigd['kwargs'] = k
f.__signature__ = sig.replace(parameters=sigd.values())
return f
return _f
# %% ../nbs/07_meta.ipynb 63
def use_kwargs(names, keep=False):
"Decorator: replace `**kwargs` in signature with `names` params"
def _f(f):
sig = inspect.signature(f)
sigd = dict(sig.parameters)
k = sigd.pop('kwargs')
s2 = {n:_mk_param(n) for n in names if n not in sigd}
sigd.update(s2)
if keep: sigd['kwargs'] = k
f.__signature__ = sig.replace(parameters=sigd.values())
return f
return _f
# %% ../nbs/07_meta.ipynb 68
def delegates(to:FunctionType=None, # Delegatee
keep=False, # Keep `kwargs` in decorated function?
but:list=None): # Exclude these parameters from signature
"Decorator: replace `**kwargs` in signature with params from `to`"
if but is None: but = []
def _f(f):
if to is None: to_f,from_f = f.__base__.__init__,f.__init__
else: to_f,from_f = to.__init__ if isinstance(to,type) else to,f
from_f = getattr(from_f,'__func__',from_f)
to_f = getattr(to_f,'__func__',to_f)
if hasattr(from_f,'__delwrap__'): return f
sig = inspect.signature(from_f)
sigd = dict(sig.parameters)
k = sigd.pop('kwargs')
s2 = {k:v.replace(kind=inspect.Parameter.KEYWORD_ONLY) for k,v in inspect.signature(to_f).parameters.items()
if v.default != inspect.Parameter.empty and k not in sigd and k not in but}
anno = {k:v for k,v in getattr(to_f, "__annotations__", {}).items() if k not in sigd and k not in but}
sigd.update(s2)
if keep: sigd['kwargs'] = k
else: from_f.__delwrap__ = to_f
from_f.__signature__ = sig.replace(parameters=sigd.values())
if hasattr(from_f, '__annotations__'): from_f.__annotations__.update(anno)
return f
return _f
# %% ../nbs/07_meta.ipynb 87
def method(f):
"Mark `f` as a method"
# `1` is a dummy instance since Py3 doesn't allow `None` any more
return MethodType(f, 1)
# %% ../nbs/07_meta.ipynb 90
def _funcs_kwargs(cls, as_method):
old_init = cls.__init__
def _init(self, *args, **kwargs):
for k in cls._methods:
arg = kwargs.pop(k,None)
if arg is not None:
if as_method: arg = method(arg)
if isinstance(arg,MethodType): arg = MethodType(arg.__func__, self)
setattr(self, k, arg)
old_init(self, *args, **kwargs)
functools.update_wrapper(_init, old_init)
cls.__init__ = use_kwargs(cls._methods)(_init)
if hasattr(cls, '__signature__'): cls.__signature__ = _rm_self(inspect.signature(cls.__init__))
return cls
# %% ../nbs/07_meta.ipynb 91
def funcs_kwargs(as_method=False):
"Replace methods in `cls._methods` with those from `kwargs`"
if callable(as_method): return _funcs_kwargs(as_method, False)
return partial(_funcs_kwargs, as_method=as_method)