pygccxml-development

[pygccxml-development] 2 Questions

[Allen B. <al...@vr...>]

I have two questions that I am surprised I haven't run into before. I 
hope that both have easy answers.

1. Base class virtual ignored, but coming in inside derived class wrappers.

I have a base class and derived class like:

struct Base
{
   virtual const int* getData() const = 0;
};

struct Child : public Base
{ }

struct GrandChild : public Child
{
   virtual const int* getData() const;
}

In my py++ generation script I ignore the getData decl in the Base class 
(and the GrandChild).  But py++ still ends up generating wrapper code 
for getData for the Child class.  To make matters worse, since it is not 
a decl for getData in the Child class I can not ignore it there.  It is 
almost like Py++ is seeing the virtual method and deciding that it needs 
to provide a wrapper for it in Child even though it is ignored in Base.  
Is this a bug in Py++ or is there some way that I can take care of this.

2. The alternative option would be to just wrap the method correctly, 
but how can I wrap returning a memory buffer (array) of arbitrary length?

Is there a way to wrap this method so it will return a const wrapper 
around this data buffer to make it look like a python list?  If so what 
is the easiest way to do it and do I really need to wait for MB's method 
transformer code to do it right?

Thanks for you help.  I am sorry if either of these seems like a really 
basic question, I just haven't run into this before.

-Allen

Re: [pygccxml-development] 2 Questions

[Roman Y. <rom...@gm...>]

On 9/12/06, Allen Bierbaum <al...@vr...> wrote:
> I have two questions that I am surprised I haven't run into before. I
> hope that both have easy answers.
>
> 1. Base class virtual ignored, but coming in inside derived class wrappers.
>
> I have a base class and derived class like:
>
> struct Base
> {
>    virtual const int* getData() const = 0;
> };
>
> struct Child : public Base
> { }
>
> struct GrandChild : public Child
> {
>    virtual const int* getData() const;
> }
>
> In my py++ generation script I ignore the getData decl in the Base class
> (and the GrandChild).  But py++ still ends up generating wrapper code
> for getData for the Child class.  To make matters worse, since it is not
> a decl for getData in the Child class I can not ignore it there.  It is
> almost like Py++ is seeing the virtual method and deciding that it needs
> to provide a wrapper for it in Child even though it is ignored in Base.
> Is this a bug in Py++ or is there some way that I can take care of this.

Do you know how hard I work to implement this? Basically this is because
wrapper classes could not be abstract. Also untill now I didn't have use case
where user ignore some method. May be I will have to take a look on it.

>
> 2. The alternative option would be to just wrap the method correctly,
> but how can I wrap returning a memory buffer (array) of arbitrary length?
>
> Is there a way to wrap this method so it will return a const wrapper
> around this data buffer to make it look like a python list?  If so what
> is the easiest way to do it and do I really need to wait for MB's method
> transformer code to do it right?

You don't have to wait, you can join and help :-). Take a look on TnFOX Python
bindings, they deal with the same problem ( image classes ). It uses indexing
suite v2 to solve the problem.


-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/

Re: [pygccxml-development] 2 Questions

[Allen B. <al...@vr...>]

Roman Yakovenko wrote:

> On 9/12/06, Allen Bierbaum <al...@vr...> wrote:
>
>> I have two questions that I am surprised I haven't run into before. I
>> hope that both have easy answers.
>>
>> 1. Base class virtual ignored, but coming in inside derived class 
>> wrappers.
>>
>> I have a base class and derived class like:
>>
>> struct Base
>> {
>>    virtual const int* getData() const = 0;
>> };
>>
>> struct Child : public Base
>> { }
>>
>> struct GrandChild : public Child
>> {
>>    virtual const int* getData() const;
>> }
>>
>> In my py++ generation script I ignore the getData decl in the Base class
>> (and the GrandChild).  But py++ still ends up generating wrapper code
>> for getData for the Child class.  To make matters worse, since it is not
>> a decl for getData in the Child class I can not ignore it there.  It is
>> almost like Py++ is seeing the virtual method and deciding that it needs
>> to provide a wrapper for it in Child even though it is ignored in Base.
>> Is this a bug in Py++ or is there some way that I can take care of this.
>
>
> Do you know how hard I work to implement this? Basically this is because
> wrapper classes could not be abstract. Also untill now I didn't have 
> use case
> where user ignore some method. May be I will have to take a look on it.

Can you give me a pointer to where the logic for this is so I can take a 
look at fixing it?

>
>>
>> 2. The alternative option would be to just wrap the method correctly,
>> but how can I wrap returning a memory buffer (array) of arbitrary 
>> length?
>>
>> Is there a way to wrap this method so it will return a const wrapper
>> around this data buffer to make it look like a python list?  If so what
>> is the easiest way to do it and do I really need to wait for MB's method
>> transformer code to do it right?
>
>
> You don't have to wait, you can join and help :-). Take a look on 
> TnFOX Python
> bindings, they deal with the same problem ( image classes ). It uses 
> indexing
> suite v2 to solve the problem.
>
This will probably be the long term solution for me.  Right now I just 
need to get my bindings compiling again so I can get some short term 
work done.

Thanks,
Allen

Re: [pygccxml-development] 2 Questions

[Roman Y. <rom...@gm...>]

On 9/12/06, Allen Bierbaum <al...@vr...> wrote:
> Can you give me a pointer to where the logic for this is so I can take a
> look at fixing it?

creator_t.redefine_funcs
Please post the fix to the list. The code in this specific function is
too fragile.

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/

Re: [pygccxml-development] 2 Questions

[Allen B. <al...@vr...>]

Allen Bierbaum wrote:

>Roman Yakovenko wrote:
>
>  
>
>>On 9/12/06, Allen Bierbaum <al...@vr...> wrote:
>>
>>    
>>
>>>I have two questions that I am surprised I haven't run into before. I
>>>hope that both have easy answers.
>>>
>>>1. Base class virtual ignored, but coming in inside derived class 
>>>wrappers.
>>>
>>>I have a base class and derived class like:
>>>
>>>struct Base
>>>{
>>>   virtual const int* getData() const = 0;
>>>};
>>>
>>>struct Child : public Base
>>>{ }
>>>
>>>struct GrandChild : public Child
>>>{
>>>   virtual const int* getData() const;
>>>}
>>>
>>>In my py++ generation script I ignore the getData decl in the Base class
>>>(and the GrandChild).  But py++ still ends up generating wrapper code
>>>for getData for the Child class.  To make matters worse, since it is not
>>>a decl for getData in the Child class I can not ignore it there.  It is
>>>almost like Py++ is seeing the virtual method and deciding that it needs
>>>to provide a wrapper for it in Child even though it is ignored in Base.
>>>Is this a bug in Py++ or is there some way that I can take care of this.
>>>      
>>>
>>Do you know how hard I work to implement this? Basically this is because
>>wrapper classes could not be abstract. Also untill now I didn't have 
>>use case
>>where user ignore some method. May be I will have to take a look on it.
>>    
>>
>
>Can you give me a pointer to where the logic for this is so I can take a 
>look at fixing it?
>  
>
Ok, this didn't work out so well.  I found a way to ignore these methods 
but this made it so the wrapper didn't generate a function at all.  
Which in turn makes the wrapper a pure class that can be instantiated 
and thus the compile fails.  It seems like what I would want here is for 
the wrapper class to generate a method but then for the exposer for the 
real class to not generate bindings for that method.  Unfortunately I 
don't see a way to do this right now. :(

-Allen

>  
>
>>>2. The alternative option would be to just wrap the method correctly,
>>>but how can I wrap returning a memory buffer (array) of arbitrary 
>>>length?
>>>
>>>Is there a way to wrap this method so it will return a const wrapper
>>>around this data buffer to make it look like a python list?  If so what
>>>is the easiest way to do it and do I really need to wait for MB's method
>>>transformer code to do it right?
>>>      
>>>
>>You don't have to wait, you can join and help :-). Take a look on 
>>TnFOX Python
>>bindings, they deal with the same problem ( image classes ). It uses 
>>indexing
>>suite v2 to solve the problem.
>>
>>    
>>
>This will probably be the long term solution for me.  Right now I just 
>need to get my bindings compiling again so I can get some short term 
>work done.
>
>Thanks,
>Allen
>
>
>-------------------------------------------------------------------------
>Using Tomcat but need to do more? Need to support web services, security?
>Get stuff done quickly with pre-integrated technology to make your job easier
>Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
>http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
>_______________________________________________
>pygccxml-development mailing list
>pyg...@li...
>https://lists.sourceforge.net/lists/listinfo/pygccxml-development
>
>  
>

Re: [pygccxml-development] 2 Questions

[Roman Y. <rom...@gm...>]

On 9/12/06, Allen Bierbaum <al...@vr...> wrote:
> Ok, this didn't work out so well.  I found a way to ignore these methods
> but this made it so the wrapper didn't generate a function at all.
> Which in turn makes the wrapper a pure class that can be instantiated
> and thus the compile fails.  It seems like what I would want here is for
> the wrapper class to generate a method but then for the exposer for the
> real class to not generate bindings for that method.  Unfortunately I
> don't see a way to do this right now. :(

You mean in class wrapper to create the function, but after this in class_<...>
not to register it right? Well the function is registered only in base class

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/