[Cython] operator() bug in cython

[Ulrich Dobramysl]

On Fri Feb 13 2015 at 11:07:39 PM Greg Ewing <greg.ewing at canterbury.ac.nz>
wrote:

> Ulrich Dobramysl wrote:
>
> > Thanks! I haven't figured out how to call heap allocated objects, as the
> > code
> > ---
> > cdef OperatorTest *t = new OperatorTest()
> > t()
> > ---
> > is not translatable by Cython.
>
> Have you tried:
>
>     t[0]()
>
> ?
>

Thanks, I didn't think about the t[0] trick!


> I haven't been following the development of Cython's internals,
> so I may be speaking naively here, but it looks wrong to me that
> the cname of that entry should be 'operator()' rather than the
> c-level name of the variable that the NameNode refers to.
>
>
The cname of the entry is correct IMO, because it cannot have any knowledge
about the cname of the object it is being called as later. The logic
dealing with the special case of an operator() member function of a c++
class in SimpleCallNode.analyse_c_function_call() needs to be changed
slightly to not treat operator() as an overloaded entry. Rather, the
function type of the SimpleCallNode needs to be set to the type of the
looked-up operator() entry. Then, at the code generation stage, the correct
cname of the SimpleCallNode entry is used and not the entry of operator().
With the patch below my test case compiles and runs without problems:
----
diff --git a/Cython/Compiler/ExprNodes.py b/Cython/Compiler/ExprNodes.py
index f99ec6e..88522c9 100644
--- a/Cython/Compiler/ExprNodes.py
+++ b/Cython/Compiler/ExprNodes.py
@@ -4569,11 +4569,13 @@ class SimpleCallNode(CallNode):
             args = self.args

         if func_type.is_cpp_class:
-            overloaded_entry =
self.function.type.scope.lookup("operator()")
-            if overloaded_entry is None:
+            call_operator = self.function.type.scope.lookup("operator()")
+            if call_operator is None:
                 self.type = PyrexTypes.error_type
                 self.result_code = "<error>"
                 return
+            self.function.type = call_operator.type
+            overloaded_entry = None
         elif hasattr(self.function, 'entry'):
             overloaded_entry = self.function.entry
         elif (isinstance(self.function, IndexNode) and
@@ -4603,7 +4605,7 @@ class SimpleCallNode(CallNode):
         else:
             entry = None
             func_type = self.function_type()
-            if not func_type.is_cfunction:
+            if not (func_type.is_cfunction or func_type.is_cpp_class):
                 error(self.pos, "Calling non-function type '%s'" %
func_type)
                 self.type = PyrexTypes.error_type
                 self.result_code = "<error>"
----
What do you think? I don't know a lot about cython's internals, so there
might be use cases which break this code.

Ulrich
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