I'm making a decorator (using functools) and I need to know if the received function is a function, class method or instance method.
I tried to use type(function)(as said here) to decide at first if it's a function or a method, but I don't understand how Python classifies them: I found that setters and getters are functions, while it should be instance methods cause they receive the parameter self.
Question: How can I distinguish between function (external, static), class methods and instance methods?
Take an example with
- External function
- Static method
- Class method
- Instance method
- Getter
- Setter
import functools
def decorator_show_type(func):
"""Decorator to get the type of setter and getter"""
@functools.wraps(func)
def tell(*args, **kwargs):
show_type(func)
return func(*args, **kwargs)
return tell
def show_type(function):
print(type(function))
def exte():
print("exte")
class Foo:
def __init__(self):
self.var = 0
@staticmethod
def stat():
print("stat")
@classmethod
def clas(cls):
print("clas")
def inst(self):
print("inst")
@property
@decorator_show_type
def var(self):
print("get var")
@var.setter
@decorator_show_type
def var(self, newvar):
print("set var")
Then, verifying the type of each function/method I get
show_type(exte) # <class 'function'>
bar = Foo() # <class 'function'>
# set var
bar.var # <class 'function'>
# get var
show_type(Foo.__init__) # <class 'function'>
show_type(Foo.stat) # <class 'function'>
show_type(Foo.clas) # <class 'method'>
show_type(Foo.inst) # <class 'function'>
show_type(bar.__init__) # <class 'method'>
show_type(bar.stat) # <class 'function'>
show_type(bar.clas) # <class 'method'>
show_type(bar.inst) # <class 'method'>
Motivation: The decorator I want to make verifies the input type of a function and raises error if it's the wrong type, like here. For external functions it works fine, but it fails for class/instance methods due the cls/self which doesn't need a type annotation.
I tried to verify if 'method' in str(type(function)): ignore first argument, but getters and setters are <class 'function'> and have the parameter self.
