python quickie : retrace function steps?

[Jeff Epler]

On Wed, Aug 20, 2003 at 09:20:29AM -0700, Matt Smith wrote:
> In perl there is a function called CALLER, which I have used to the
> same effect, i was wondering if python had something similar for this?

Python has sys._getframe, and various frame-oriented functions in the
inspect module that build on sys._getframe.

$ cat /tmp/smith.py
from __future__ import generators

import inspect

try: enumerate
except NameError:
    def enumerate(l):
        idx = 0
        for item in l:
            yield idx, item
            idx += 1

def f(): g()

def g(): h()

def h():
    print_callers()

def print_callers():
    for record in inspect.getouterframes(inspect.currentframe(1), 2):
        print "%s() at %s:%d" % (record[3], record[1], record[2])
        for idx, line in enumerate(record[4]):
            print "%03d: %s" % ( idx + record[2] - 1, line.strip("\n"))
        print

# Let's show something interesting
f()

$ python /tmp/smith.py
h() at /tmp/smith.py:18
017: def h():
018:     print_callers()

g() at /tmp/smith.py:15
014: 
015: def g(): h()

f() at /tmp/smith.py:13
012: 
013: def f(): g()

?() at /tmp/smith.py:28
027: # Let's show something interesting
028: f()

Jeff