Added type checking when converting some Python types from python as return values.

[SVN r14478]

test/list.cpp

@@ -38,6 +38,11 @@ object apply_object_list(object f, list x)
     return f(x);
 }
 
+list apply_list_list(object f, list x)
+{
+    return call<list>(f.ptr(), x);
+}
+
 void append_object(list& x, object y)
 {
     x.append(y);
@@ -126,6 +131,7 @@ BOOST_PYTHON_MODULE_INIT(list_ext)
         .def("listify", listify)
         .def("listify_string", listify_string)
         .def("apply_object_list", apply_object_list)
+        .def("apply_list_list", apply_list_list)
         
         .def("append_object", append_object)
         .def("append_list", append_list)

test/list.py

@@ -20,9 +20,17 @@ X(22)
 
   5 is not convertible to a list
 
->>> try: apply_object_list(identity, 5)
+>>> try: result = apply_object_list(identity, 5)
 ... except TypeError: pass
-... else: print 'expected an exception'
+... else: print 'expected an exception, got', result, 'instead'
+
+>>> assert apply_list_list(identity, letters) is letters
+
+  5 is not convertible to a list as a return value
+
+>>> try: result = apply_list_list(len, letters)
+... except TypeError: pass
+... else: print 'expected an exception, got', result, 'instead'
 
 >>> append_object(letters, '.')
 >>> letters
@@ -38,6 +46,24 @@ X(22)
 >>> letters
 ['h', 'e', 'l', 'l', 'o', '.', [1, 2]]
 
+    Check that subclass functions are properly called
+    
+>>> class mylist(list):
+...     def append(self, o):
+...         list.append(self, o)
+...         if not hasattr(self, 'nappends'):
+...             self.nappends = 1
+...         else:
+...             self.nappends += 1
+...
+>>> l2 = mylist()
+>>> append_object(l2, 'hello')
+>>> append_object(l2, 'world')
+>>> l2
+['hello', 'world']
+>>> l2.nappends
+2
+
 >>> def printer(*args):
 ...     for x in args: print x,
 ...     print