[PyQt] SIP: deriving a python class from a C++ ABC results in a TypeError exception
I have a C++ class which is declared with pure virtual methods, but if I
derive from this class in python and implement the pure virtual methods, I
get an exception:
TypeError: pyvoip.opal.OpalPCSSEndPoint cannot be instantiated or
sub-classed
My python class is declared as following:
class PCSSEndPoint(OpalPCSSEndPoint):
def __init__(self):
super(OpalPCSSEndPoint, self).__init__()
def OnShowIncoming(self, connection):
return True
def OnShowOutgoing(self, connection):
return True
def GetMediaFormats(self):
return []
SIP definitions:
class OpalPCSSEndPoint : OpalLocalEndPoint /Abstract/
{
/**Call back to indicate that remote is ringing.
If false is returned the call is aborted.
The default implementation is pure.
*/
virtual PBoolean OnShowIncoming(
const OpalPCSSConnection & connection /NoCopy/ ///< Connection having event
) = 0;
/**Call back to indicate that remote is ringing.
If false is returned the call is aborted.
The default implementation is pure.
*/
virtual PBoolean OnShowOutgoing(
const OpalPCSSConnection & connection /NoCopy/ ///< Connection having event
) = 0;
};
Now the base class of OpalPCSSEndPoint is also an ABC, as it derives from an
ABC but does not re-define the pure virtual function:
class OpalLocalEndPoint : OpalEndPoint /Abstract/
{
...
};
class OpalEndPoint /Abstract/
{
virtual OpalMediaFormatList GetMediaFormats() const = 0;
};
I tried removing /Abstract/ from OpalLocalEndPoint, but it made no
difference. Any idea what's wrong in this scenario? The only way this
works, is if I subclass OpalPCSSEndPoint in C++ and then in Python create a
class derived from my OpalPCSSEndPoint subclass.
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Re: [PyQt] SIP: deriving a python class from a C++ ABC results in a TypeError exception
Actually I made a small mistake, OpalLocalEndPoint has a GetMediaFormats
implementation, but the issue remains.
class OpalLocalEndPoint : OpalEndPoint
{
virtual OpalMediaFormatList GetMediaFormats() const;
};
On Sat, Jul 2, 2011 at 5:39 PM, Demetrius Cassidy wrote:
> I have a C++ class which is declared with pure virtual methods, but if I
> derive from this class in python and implement the pure virtual methods, I
> get an exception:
> TypeError: pyvoip.opal.OpalPCSSEndPoint cannot be instantiated or
> sub-classed
>
> My python class is declared as following:
>
> class PCSSEndPoint(OpalPCSSEndPoint):
> def __init__(self):
> super(OpalPCSSEndPoint, self).__init__()
>
> def OnShowIncoming(self, connection):
> return True
>
> def OnShowOutgoing(self, connection):
> return True
>
> def GetMediaFormats(self):
> return []
>
>
> SIP definitions:
>
> class OpalPCSSEndPoint : OpalLocalEndPoint /Abstract/
> {
>
> /**Call back to indicate that remote is ringing.
> If false is returned the call is aborted.
>
> The default implementation is pure.
> */
> virtual PBoolean OnShowIncoming(
> const OpalPCSSConnection & connection /NoCopy/ ///< Connection having event
> ) = 0;
>
> /**Call back to indicate that remote is ringing.
> If false is returned the call is aborted.
>
> The default implementation is pure.
> */
> virtual PBoolean OnShowOutgoing(
> const OpalPCSSConnection & connection /NoCopy/ ///< Connection having event
> ) = 0;
>
> };
>
> Now the base class of OpalPCSSEndPoint is also an ABC, as it derives from
> an ABC but does not re-define the pure virtual function:
>
> class OpalLocalEndPoint : OpalEndPoint /Abstract/
> {
> ...
> };
>
> class OpalEndPoint /Abstract/
> {
> virtual OpalMediaFormatList GetMediaFormats() const = 0;
> };
>
> I tried removing /Abstract/ from OpalLocalEndPoint, but it made no
> difference. Any idea what's wrong in this scenario? The only way this
> works, is if I subclass OpalPCSSEndPoint in C++ and then in Python create a
> class derived from my OpalPCSSEndPoint subclass.
>
>
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Re: [PyQt] SIP: deriving a python class from a C++ ABC results in a TypeError exception
On Sat, 2 Jul 2011 17:39:14 +, Demetrius Cassidy
wrote:
> I have a C++ class which is declared with pure virtual methods, but if I
> derive from this class in python and implement the pure virtual methods,
I
> get an exception:
> TypeError: pyvoip.opal.OpalPCSSEndPoint cannot be instantiated or
> sub-classed
>
> My python class is declared as following:
>
> class PCSSEndPoint(OpalPCSSEndPoint):
> def __init__(self):
> super(OpalPCSSEndPoint, self).__init__()
That should be super(PCSSEndPoint, self).__init__()
> def OnShowIncoming(self, connection):
> return True
>
> def OnShowOutgoing(self, connection):
> return True
>
> def GetMediaFormats(self):
> return []
>
>
> SIP definitions:
>
> class OpalPCSSEndPoint : OpalLocalEndPoint /Abstract/
> {
>
> /**Call back to indicate that remote is ringing.
> If false is returned the call is aborted.
>
> The default implementation is pure.
> */
> virtual PBoolean OnShowIncoming(
> const OpalPCSSConnection & connection /NoCopy/ ///< Connection having
event
> ) = 0;
>
> /**Call back to indicate that remote is ringing.
> If false is returned the call is aborted.
>
> The default implementation is pure.
> */
> virtual PBoolean OnShowOutgoing(
> const OpalPCSSConnection & connection /NoCopy/ ///< Connection having
event
> ) = 0;
>
> };
>
> Now the base class of OpalPCSSEndPoint is also an ABC, as it derives
from
> an
> ABC but does not re-define the pure virtual function:
>
> class OpalLocalEndPoint : OpalEndPoint /Abstract/
> {
> ...
> };
>
> class OpalEndPoint /Abstract/
> {
> virtual OpalMediaFormatList GetMediaFormats() const = 0;
> };
>
> I tried removing /Abstract/ from OpalLocalEndPoint, but it made no
> difference. Any idea what's wrong in this scenario? The only way this
> works, is if I subclass OpalPCSSEndPoint in C++ and then in Python
create a
> class derived from my OpalPCSSEndPoint subclass.
/Abstract/ is the cause of the problem. It doesn't mean that the C++ is an
ABC, it means that the class contains other (unspecified) abstract methods.
Phil
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Re: [PyQt] SIP: deriving a python class from a C++ ABC results in a TypeError exception
CCing mailing list
On Sat, Jul 2, 2011 at 10:50 PM, Demetrius Cassidy wrote:
> On Sat, Jul 2, 2011 at 10:45 PM, Phil Thompson <
> p...@riverbankcomputing.com> wrote:
>
>> On Sat, 2 Jul 2011 17:39:14 +, Demetrius Cassidy
>>
>> wrote:
>> > I have a C++ class which is declared with pure virtual methods, but if I
>> > derive from this class in python and implement the pure virtual methods,
>> I
>> > get an exception:
>> > TypeError: pyvoip.opal.OpalPCSSEndPoint cannot be instantiated or
>> > sub-classed
>> >
>> > My python class is declared as following:
>> >
>> > class PCSSEndPoint(OpalPCSSEndPoint):
>> > def __init__(self):
>> > super(OpalPCSSEndPoint, self).__init__()
>>
>> That should be super(PCSSEndPoint, self).__init__()
>>
>
> The super thing was a typo.
>
>>
>> > def OnShowIncoming(self, connection):
>> > return True
>> >
>> > def OnShowOutgoing(self, connection):
>> > return True
>> >
>> > def GetMediaFormats(self):
>> > return []
>> >
>> >
>> > SIP definitions:
>> >
>> > class OpalPCSSEndPoint : OpalLocalEndPoint /Abstract/
>> > {
>> >
>> > /**Call back to indicate that remote is ringing.
>> > If false is returned the call is aborted.
>> >
>> > The default implementation is pure.
>> > */
>> > virtual PBoolean OnShowIncoming(
>> > const OpalPCSSConnection & connection /NoCopy/ ///< Connection having
>> event
>> > ) = 0;
>> >
>> > /**Call back to indicate that remote is ringing.
>> > If false is returned the call is aborted.
>> >
>> > The default implementation is pure.
>> > */
>> > virtual PBoolean OnShowOutgoing(
>> > const OpalPCSSConnection & connection /NoCopy/ ///< Connection having
>> event
>> > ) = 0;
>> >
>> > };
>> >
>> > Now the base class of OpalPCSSEndPoint is also an ABC, as it derives
>> from
>> > an
>> > ABC but does not re-define the pure virtual function:
>> >
>> > class OpalLocalEndPoint : OpalEndPoint /Abstract/
>> > {
>> > ...
>> > };
>> >
>> > class OpalEndPoint /Abstract/
>> > {
>> > virtual OpalMediaFormatList GetMediaFormats() const = 0;
>> > };
>> >
>> > I tried removing /Abstract/ from OpalLocalEndPoint, but it made no
>> > difference. Any idea what's wrong in this scenario? The only way this
>> > works, is if I subclass OpalPCSSEndPoint in C++ and then in Python
>> create a
>> > class derived from my OpalPCSSEndPoint subclass.
>>
>> /Abstract/ is the cause of the problem. It doesn't mean that the C++ is an
>> ABC, it means that the class contains other (unspecified) abstract
>> methods.
>>
>> Phil
>>
>
> So if /Abstract/ does not mean the class has pure virtual methods and
> cannot be instantiated itself, in which scenario should it be used? I'm a
> little confused here.
>
>
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Re: [PyQt] SIP: deriving a python class from a C++ ABC results in a TypeError exception
I think I answered my own question after re-reading the annotation docs.
Thanks.
On Sat, Jul 2, 2011 at 10:52 PM, Demetrius Cassidy wrote:
> CCing mailing list
>
>
> On Sat, Jul 2, 2011 at 10:50 PM, Demetrius Cassidy
> wrote:
>
>> On Sat, Jul 2, 2011 at 10:45 PM, Phil Thompson <
>> p...@riverbankcomputing.com> wrote:
>>
>>> On Sat, 2 Jul 2011 17:39:14 +, Demetrius Cassidy
>>>
>>> wrote:
>>> > I have a C++ class which is declared with pure virtual methods, but if
>>> I
>>> > derive from this class in python and implement the pure virtual
>>> methods,
>>> I
>>> > get an exception:
>>> > TypeError: pyvoip.opal.OpalPCSSEndPoint cannot be instantiated or
>>> > sub-classed
>>> >
>>> > My python class is declared as following:
>>> >
>>> > class PCSSEndPoint(OpalPCSSEndPoint):
>>> > def __init__(self):
>>> > super(OpalPCSSEndPoint, self).__init__()
>>>
>>> That should be super(PCSSEndPoint, self).__init__()
>>>
>>
>> The super thing was a typo.
>>
>>>
>>> > def OnShowIncoming(self, connection):
>>> > return True
>>> >
>>> > def OnShowOutgoing(self, connection):
>>> > return True
>>> >
>>> > def GetMediaFormats(self):
>>> > return []
>>> >
>>> >
>>> > SIP definitions:
>>> >
>>> > class OpalPCSSEndPoint : OpalLocalEndPoint /Abstract/
>>> > {
>>> >
>>> > /**Call back to indicate that remote is ringing.
>>> > If false is returned the call is aborted.
>>> >
>>> > The default implementation is pure.
>>> > */
>>> > virtual PBoolean OnShowIncoming(
>>> > const OpalPCSSConnection & connection /NoCopy/ ///< Connection having
>>> event
>>> > ) = 0;
>>> >
>>> > /**Call back to indicate that remote is ringing.
>>> > If false is returned the call is aborted.
>>> >
>>> > The default implementation is pure.
>>> > */
>>> > virtual PBoolean OnShowOutgoing(
>>> > const OpalPCSSConnection & connection /NoCopy/ ///< Connection having
>>> event
>>> > ) = 0;
>>> >
>>> > };
>>> >
>>> > Now the base class of OpalPCSSEndPoint is also an ABC, as it derives
>>> from
>>> > an
>>> > ABC but does not re-define the pure virtual function:
>>> >
>>> > class OpalLocalEndPoint : OpalEndPoint /Abstract/
>>> > {
>>> > ...
>>> > };
>>> >
>>> > class OpalEndPoint /Abstract/
>>> > {
>>> > virtual OpalMediaFormatList GetMediaFormats() const = 0;
>>> > };
>>> >
>>> > I tried removing /Abstract/ from OpalLocalEndPoint, but it made no
>>> > difference. Any idea what's wrong in this scenario? The only way this
>>> > works, is if I subclass OpalPCSSEndPoint in C++ and then in Python
>>> create a
>>> > class derived from my OpalPCSSEndPoint subclass.
>>>
>>> /Abstract/ is the cause of the problem. It doesn't mean that the C++ is
>>> an
>>> ABC, it means that the class contains other (unspecified) abstract
>>> methods.
>>>
>>> Phil
>>>
>>
>> So if /Abstract/ does not mean the class has pure virtual methods and
>> cannot be instantiated itself, in which scenario should it be used? I'm a
>> little confused here.
>>
>>
>
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