Re: [Swig-user] std::vector::size_type wrapped as a pointer not an integer

[William S F. <ws...@fu...>]

On 20/06/11 01:13, Aubrey Barnard wrote:
> On 06/16/2011 02:32 PM, Stefan Zager wrote:
>> On Wed, Jun 15, 2011 at 2:37 PM, Aubrey Barnard<ba...@cs...
>> <mailto:ba...@cs...>>  wrote:
>>
>>      Knowing this all has to do with typemaps, the last thing I tried was
>>      telling Swig to apply an existing typemap to the type in question. I
>>      don't think I did this correctly as size_type is not a pointer, but I'm
>>      not clear on the details (syntax, matching) of specifying the arguments
>>      for most of the Swig directives, including %apply.
>>      %apply unsigned long *OUTPUT { std::vector::size_type };
>>
>>      That's where I am at. Clearly there are gaps in my understanding of Swig
>>      (despite re-reading the apparently relevant sections of the manual), and
>>      that is why I am asking for some help with this.
>>
>>
>> I think you're on the right track with %typemap.  Try providing a
>> %typemap for each %template instance, something like this:
>>
>> %apply size_t { std::vector<int>::size_type };
>> %template(SmallSetInt) SmallSet<int>;
>>
>> %apply size_t { std::vector<double>::size_type };
>> %template(SmallSetDouble) SmallSet<double>;
>>
>>
Yes, except the %apply should not be necessary. It looks like there is a 
failure in the typedef resolution for templates with default template 
parameters - std::vector has a default parameter for the allocator. I'll 
see if I can track this down and fix... deep breath.

>> Stefan
>
> Stefan,
>
> Thanks for the suggestion. It worked. I tried a few variants but
>
> %apply size_t { std::vector<int>::size_type };
>
> was the minimal solution I was able to get to work.
>
> -----
> As a note to all those who might encounter similar problems in the
> future, I found it helpful to run with '-debug-tmused' to see what
> typemaps Swig applied to the method in question (grep helped). Once I
> was able to see that, it was easy to see when I had fixed the problem
> and had Swig doing what I want. Further, importing/including
> std_vector.i complicates things slightly as the vector type changes and
> so the following line is required instead of the one above.
>
> %apply size_t { std::vector<int,std::allocator<int>>::size_type };
>
> You do not need to include a typedef for size_t as Swig already knows
> what that is.
> -----
>
> I am still curious (but rhetorically so) why my first idea of including
> std_vector.i did not work. The typedef equating size_t and size_type is
> in std_vector.i so it seems like that should be enough.
>
This is all that *should* be needed:

%include <std_vector.i>

// Named or unnamed %template can be used in this instance
//%template(VectorInt) std::vector<size_t>;
%template() std::vector<size_t>;

%inline %{
#include <vector>
template<typename T> class SmallSet {
public:
    typename std::vector<T>::size_type size() const;
};
%}

%template(SmallSetInt) SmallSet<size_t>;

In fact this does work with Java wrappers because the std::vector 
declaration used in Java does not have the allocator.

William