How to print graph call as tree?

Question

For instanse, I have the following code snippet:

def func1(num):
    print(num)

def func2(num):
    func1(num)

def func3(num):
    func2(num)
    func1(num)

def begin():
    pass

def print_graph():
    pass


def main():
    begin()
    func3(3)
    print_graph()

Is there any simple way to print something like that:

func3(1)
    func2(1)
        func1(1)
    func1(1)

I believe, that I have to use globals(), but I don't know, what I do next. It is some sort of study task, therefore I cant use any libraries.

Answer 1

How about using decorators to print a function's name when it is called? Something like this:

from functools import wraps

def print_on_entry(fn):
    @wraps(fn)
    def wrapper(*args):
        print "{}({})".format(fn.func_name, ", ".join(str(a) for a in args))
        fn(*args)
    return wrapper

Then you can wrap each of your functions up:

func1 = print_on_entry(func1)
func2 = print_on_entry(func2)
func3 = print_on_entry(func3)

So that:

>>> func3(1)
func3(1)
func2(1)
func1(1)
1
func1(1)
1

Of course there are a lot of assumptions in the above code -- the arguments can be converted to strings, for example -- but you get the picture.