more robust docstring parsing and docstring parser test

now it can parse cython method like
Minuit.migrad(self, int ncall=10000, resume=True, int nsplit=1)\n

IPython/core/completer.py

@@ -670,12 +670,13 b' class IPCompleter(Completer):'
         form 'min(iterable[, key=func])\n' to find
         keyword argument names.
         """
+        if doc is None: return []
         doc = doc.lstrip()
         sio = StringIO.StringIO(doc)
         #care only the firstline
         #docstring can be long
         line = sio.readline()
-        p = re.compile(r'^[\w]+\(([^)]*)\).*')
+        p = re.compile(r'^[\w|\s.]+\(([^)]*)\).*')
         #'min(iterable[, key=func])\n' -> 'iterable[, key=func]'
         sig = p.search(line)
         if sig is None: return []
@@ -686,9 +687,7 b' class IPCompleter(Completer):'
         q = re.compile('[\s|\[]*(\w+)(?:\s*=\s*.*)')
         ret = []
         for s in sig:
-            tmp = q.match(s)
-            if tmp is not None:
-                ret.append(tmp.groups()[0])
+            ret += q.findall(s)
         return ret
 
     def _default_arguments(self, obj):
@@ -697,24 +696,23 b' class IPCompleter(Completer):'
         call_obj = obj
         ret = []
         if inspect.isbuiltin(obj):
-            #parse builtin docstring for signature
+            pass
+        elif not (inspect.isfunction(obj) or inspect.ismethod(obj)):
+            #for cython embededsignature=True the docstring belongs to
+            #the object itself not __init__ or __call__
             ret+=self._default_arguments_from_docstring(
                  getattr(obj,'__doc__',''))
-        elif not (inspect.isfunction(obj) or inspect.ismethod(obj)):
-            # for classes, check for __init__,__new__
             if inspect.isclass(obj):
-                #for cython embded signature it puts
-                #__init__ signature in class docstring not __init__'s one
-                ret = self._default_arguments_from_docstring(
-                        getattr(obj,'__doc__',''))
+                # for classes, check for __init__,__new__
                 call_obj = (getattr(obj,'__init__',None) or
                        getattr(obj,'__new__',None))
-                ret += self._default_arguments_from_docstring(
-                        getattr(all_obj,'__doc__',''))
             # for all others, check if they are __call__able
             elif hasattr(obj, '__call__'):
                 call_obj = obj.__call__
 
+        ret += self._default_arguments_from_docstring(
+                 getattr(call_obj,'__doc__',''))
+
         try:
             args,_,_1,defaults = inspect.getargspec(call_obj)
             if defaults:

IPython/core/tests/test_completer.py

@@ -297,6 +297,22 b' def test_func_kw_completions():'
     nt.assert_in('key=', matches)
 
 
+def test_default_arguments_from_docstring():
+    doc = min.__doc__
+    ip = get_ipython()
+    c = ip.Completer
+    kwd = c._default_arguments_from_docstring(
+        'min(iterable[, key=func]) -> value')
+    nt.assert_equal(kwd,['key'])
+    #with cython type etc
+    kwd = c._default_arguments_from_docstring(
+        'Minuit.migrad(self, int ncall=10000, resume=True, int nsplit=1)\n')
+    nt.assert_equal(kwd,['ncall','resume','nsplit'])
+    #white spaces
+    kwd = c._default_arguments_from_docstring(
+        '\n Minuit.migrad(self, int ncall=10000, resume=True, int nsplit=1)\n')
+    nt.assert_equal(kwd,['ncall','resume','nsplit'])
+
 def test_line_magics():
     ip = get_ipython()
     c = ip.Completer