Implement decided resolution of #304

- Remove self for normal callables
- Retain self for methods (of course)
- Add decorator to retrieve self for special callbacks that need it
  (Yes, the example is kinda stupid and would be unnecessary with #300)

i3pystatus/core/modules.py

@@ -1,3 +1,5 @@
+import inspect
+
 from i3pystatus.core.settings import SettingsBase
 from i3pystatus.core.threading import Manager
 from i3pystatus.core.util import (convert_position,
@@ -6,6 +8,14 @@ from i3pystatus.core.command import execute
 from i3pystatus.core.command import run_through_shell
 
 
+def is_method_of(method, object):
+    """Decide whether ``method`` is contained within the MRO of ``object``."""
+    for cls in inspect.getmro(object.__class__):
+        if method in cls.__dict__.values():
+            return True
+    return False
+
+
 class Module(SettingsBase):
     output = None
     position = 0
@@ -80,8 +90,11 @@ class Module(SettingsBase):
         else:
             args = []
 
-        if callable(cb):
+        our_method = is_method_of(cb, self)
+        if callable(cb) and not our_method:
             self.__log_button_event(button, cb, args, "Python callback")
+            cb(*args)
+        elif our_method:
             cb(self, *args)
         elif hasattr(self, cb):
             if cb is not "run":

i3pystatus/core/util.py

@@ -3,7 +3,7 @@ import functools
 import re
 import socket
 import string
-
+import inspect
 from threading import Timer, RLock
 
 
@@ -558,3 +558,32 @@ class MultiClickHandler(object):
 
         self.clear_timer()
         return ret
+
+
+def get_module(function):
+    """Function decorator for retrieving the ``self`` argument from the stack.
+
+    Intended for use with callbacks that need access to a modules variables, for example:
+
+    .. code:: python
+
+        from i3pystatus import Status
+        from i3pystatus.core.util import get_module
+        from i3pystatus.core.command import execute
+        status = Status(...)
+        # other modules etc.
+        @get_module
+        def display_ip_verbose(module):
+            execute('sh -c "ip addr show dev {dev} | xmessage -file -"'.format(dev=module.interface))
+        status.register("network", interface="wlan1", on_leftclick=display_ip_verbose)
+    """
+    @functools.wraps(function)
+    def call_wrapper(*args, **kwargs):
+        stack = inspect.stack()
+        caller_frame_info = stack[1]
+        self = caller_frame_info[0].f_locals["self"]
+        # not completly sure whether this is necessary
+        # see note in Python docs about stack frames
+        del stack
+        function(self, *args, **kwargs)
+    return call_wrapper