Constructs a inspect.Signature object for a type.
It uses the class-level annotations as the parameters so
that we can treat the classes and functions the same
Source code in /home/sean/sourcecode/arc/arc/define/classful.py
| def class_signature(cls: type) -> inspect.Signature:
"""Constructs a `inspect.Signature` object for a type.
It uses the class-level annotations as the parameters so
that we can treat the classes and functions the same
"""
annotations = t.get_type_hints(cls, include_extras=True)
defaults = {name: getattr(cls, name) for name in dir(cls) if not isdunder(name)}
attrs = {}
for name, annotation in annotations.items():
attrs[name] = (annotation, inspect.Parameter.empty)
for name, default in defaults.items():
if inspect.isfunction(default):
continue
if name in attrs:
attrs[name] = (attrs[name][0], default)
else:
attrs[name] = (t.Any, default)
parameters = [
inspect.Parameter(
name=name,
kind=inspect.Parameter.POSITIONAL_OR_KEYWORD,
default=default,
annotation=annotation,
)
for name, (annotation, default) in attrs.items()
]
sig = inspect.Signature(
sorted(parameters, key=lambda p: not p.default is inspect.Parameter.empty)
)
# inspect.signature() checks for a cached signature object
# at __signature__. So we can cache it there
# to generate the correct signature object
# during the parameter building process
setattr(cls, "__signature__", sig)
return sig
|