allow interact(instancemethod)

objects that can't have `.widget` attribute assigned
are wrapped in a lambda

IPython/html/widgets/interaction.py

@@ -1,16 +1,7 @@
 """Interact with functions using widgets."""
 
-#-----------------------------------------------------------------------------
-# Copyright (c) 2013, the IPython Development Team.
-#
+# Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
-#
-# The full license is in the file COPYING.txt, distributed with this software.
-#-----------------------------------------------------------------------------
-
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
 
 from __future__ import print_function
 
@@ -30,10 +21,6 @@ from IPython.utils.traitlets import HasTraits, Any, Unicode
 
 empty = Parameter.empty
 
-#-----------------------------------------------------------------------------
-# Classes and Functions
-#-----------------------------------------------------------------------------
-
 
 def _matches(o, pattern):
     """Match a pattern of types in a sequence."""
@@ -251,7 +238,13 @@ def interact(__interact_f=None, **kwargs):
         #        ...
         f = __interact_f
         w = interactive(f, **kwargs)
-        f.widget = w
+        try:
+            f.widget = w
+        except AttributeError:
+            # some things (instancemethods) can't have attributes attached,
+            # so wrap in a lambda
+            f = lambda *args, **kwargs: __interact_f(*args, **kwargs)
+            f.widget = w
         display(w)
         return f
     else:
@@ -260,10 +253,7 @@ def interact(__interact_f=None, **kwargs):
         # def f(*args, **kwargs):
         #     ...
         def dec(f):
-            w = interactive(f, **kwargs)
-            f.widget = w
-            display(w)
-            return f
+            return interact(f, **kwargs)
         return dec
 
 def interact_manual(__interact_f=None, **kwargs):

IPython/html/widgets/tests/test_interaction.py

@@ -365,6 +365,23 @@ def test_decorator_kwarg():
         value=5,
     )
 
+@nt.with_setup(clear_display)
+def test_interact_instancemethod():
+    class Foo(object):
+        def show(self, x):
+            print(x)
+
+    f = Foo()
+    
+    with tt.monkeypatch(interaction, 'display', record_display):
+        g = interact(f.show, x=(1,10))
+    nt.assert_equal(len(displayed), 1)
+    w = displayed[0].children[0]
+    check_widget(w,
+        cls=widgets.IntSlider,
+        value=5,
+    )
+
 @nt.with_setup(clear_display)
 def test_decorator_no_call():
     with tt.monkeypatch(interaction, 'display', record_display):