[Swig-user] Is there a workaround to use %template after reading all header files?

[James M. <jam...@gm...>]

Hi all,

I am attempting to wrap a very large set of C++ classes (for Ruby) of which
I do not own the header files.  I am having an issue with wrapping templates
and using those templates as a base class.  Here is a simplified example of
a header file:

template <class T> class ArrayBase {};
template <class T> class Array : public ArrayBase<T> {};
class IntArray : public Array<int> {};

According to my knowledge, in order to properly wrap the templates Array and
ArrayBase and in order to have inheritance work properly, I need to somehow
put %template declarations after the template definitions but before a class
derives from a template instantiation.  So in other words, I would need the
SWIG interface to look like this:

template <class T> class ArrayBase {};
template <class T> class Array : public ArrayBase<T> {};
%template("IArrayBase") ArrayBase<int>;
%template("IArray") Array<int>;
class IntArray : public Array<int> {};

Given that I do not own the header files, I cannot embed %template in
between as shown above.  I would really like to just define %template after
the header files are read in, but that results in:

% swig -ruby -c++ basetest.i
basetest.i:7: Warning(401): Base class 'Array< int >' undefined.
basetest.i:10: Warning(401): 'Array< int >' must be defined before it is
used as a base class.

And in the generated code IntArray does not inherit from Array<int>.  Please
advise if there is a work-around to this situation.

Thanks,
-James