1import functools
2import inspect
3
4
5@functools.lru_cache(maxsize=512)
6def _get_func_parameters(func, remove_first):
7 parameters = tuple(inspect.signature(func).parameters.values())
8 if remove_first:
9 parameters = parameters[1:]
10 return parameters
11
12
13def _get_callable_parameters(meth_or_func):
14 is_method = inspect.ismethod(meth_or_func)
15 func = meth_or_func.__func__ if is_method else meth_or_func
16 return _get_func_parameters(func, remove_first=is_method)
17
18
19ARG_KINDS = frozenset(
20 {
21 inspect.Parameter.POSITIONAL_ONLY,
22 inspect.Parameter.KEYWORD_ONLY,
23 inspect.Parameter.POSITIONAL_OR_KEYWORD,
24 }
25)
26
27
28def get_func_args(func):
29 params = _get_callable_parameters(func)
30 return [param.name for param in params if param.kind in ARG_KINDS]
31
32
33def get_func_full_args(func):
34 """
35 Return a list of (argument name, default value) tuples. If the argument
36 does not have a default value, omit it in the tuple. Arguments such as
37 *args and **kwargs are also included.
38 """
39 params = _get_callable_parameters(func)
40 args = []
41 for param in params:
42 name = param.name
43 # Ignore 'self'
44 if name == "self":
45 continue
46 if param.kind == inspect.Parameter.VAR_POSITIONAL:
47 name = "*" + name
48 elif param.kind == inspect.Parameter.VAR_KEYWORD:
49 name = "**" + name
50 if param.default != inspect.Parameter.empty:
51 args.append((name, param.default))
52 else:
53 args.append((name,))
54 return args
55
56
57def func_accepts_kwargs(func):
58 """Return True if function 'func' accepts keyword arguments **kwargs."""
59 return any(p for p in _get_callable_parameters(func) if p.kind == p.VAR_KEYWORD)
60
61
62def func_accepts_var_args(func):
63 """
64 Return True if function 'func' accepts positional arguments *args.
65 """
66 return any(p for p in _get_callable_parameters(func) if p.kind == p.VAR_POSITIONAL)
67
68
69def method_has_no_args(meth):
70 """Return True if a method only accepts 'self'."""
71 count = len([p for p in _get_callable_parameters(meth) if p.kind in ARG_KINDS])
72 return count == 0 if inspect.ismethod(meth) else count == 1
73
74
75def func_supports_parameter(func, name):
76 return any(param.name == name for param in _get_callable_parameters(func))