[Swig-user] Problematic template class to wrap

[patb <cr...@ol...>]

Hello,

I need help wrapping two classes. One of the classes (the problematic one)
is a template, which is derived from a class, given by one of it's own
template parameters. Please have a look:


Class "World" (simplified), this class is not that problematic, but it uses
the problematic class:

___________________

class World
{
private:
  typedef std::vector<Node*> NodeVector;

public:      
  typedef SkipNullIterator< const Node, NodeVector,
NodeVector::const_iterator > const_node_iterator;
  typedef SkipNullIterator< Node, NodeVector, NodeVector::iterator>
node_iterator;

  const_node_iterator begin_nodes( void ) const throw();
  node_iterator begin_nodes_w( void ) throw();
  
  // ...snip... //
};
___________________


Second class "SkipNullIterator" (simplified, the problematic one!):

___________________

template< typename VAL, typename C, typename IT > class SkipNullIterator :
public IT
{
public:
  typedef VAL value_type;
  typedef C container_type;
  typedef IT base_type;
  
  typedef SkipNullIterator<VAL, C, IT> self_type;
  
  // ...snip... //
};
___________________


As you can see, the second class, "SkipNullIterator", is beeing derived from
IT, which is the template parameter IT. Basically, I just want to wrap the
class "World". But in turn I also have to wrap "SkipNullIterator" and
because it is a template class, I have to instantiate it the way the World
class is using it.


My attempt to wrap "SkipNullIterator" looks like this (skipnull_iterator.i):
___________________

%{
	#include "skipnull_iterator.h"
%}

%include "skipnull_iterator.h";

%include "std_vector.i";
%template( vector_node ) std::vector< Node* >;

%template( skipnull_iterator_world_const )
	shawn::SkipNullIterator< const Node,
							 vector_node,
							 vector_node::const_iterator >;
___________________


Swig prints out the following warning:
___________________

skipnull_iterator.i:13: Warning(401): Nothing known about base class
'vector_node::const_iterator'. Ignored.
___________________


I understand that Swig does not know the base class
vector_node::const_iterator (it is the base class, because it is the third
template parameter for SkipNullIterator, from which SkipNullIterator
derives), so I tried the following:

___________________

%{
	#include "../src/sys/misc/skipnull_iterator.h"
%}

%include "../src/sys/misc/skipnull_iterator.h";

%include "std_vector.i";
%template( vector_node ) std::vector< shawn::Node* >;
%template( vector_node_constit ) std::vector< shawn::Node*
>::const_iterator;

%template( skipnull_iterator_world_const )
	shawn::SkipNullIterator< const shawn::Node,
							 vector_node,
							 vector_node_constit >;
___________________


I don't know if that makes sense at all, but I do not know how to tell Swig
about the ::const_iterator. The interface code above produces a syntax error
"skipnull_iterator.i:9: Error: Syntax error in input(1).".


Note: In the code snippets above I always use "std::vector< Node* >", but
the class world.h useses a typedef "typedef std::vector<Node*> NodeVector;"
If there is a possibility to use the "NodeVector" typedef in the interface
file, that would be great, but it is not a must.


Please, it would be great if anyone can tell me how to correctly wrap the
class "SkipNullIterator" and instantiate the needed template.


Thanks a lot for your help!
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