Question

In the boost graph library, there are property maps used. For an example, consider this link about properties. You can add multiple properties list like:

typedef property<vertex_distance_t, float, 
    property<vertex_name_t, std::string> > VertexProperty;

My questions are:

• Is there a name for this “list of templates” concept, so I can google it?
• Are there similar advanced template structures, like arrays or trees?
• Do you have a good book or weblink explaining it?

Note: I need a solution without C++11, though C++11 would be interesting, too.

Answer 1

This type of template composition is called base class chaining.

It specifically works nicely to

• profit from empty baseclass optimizations
• making it relatively easy to support open-ended lists of mixins, even on compilers that don’t directly support variadics yet
  

  Edit In fact, indeed this was how typelists were usually implemented before the advent of (c++0x) variadics (Modern C++ Design)

References:

• Base Class Chaining and Object Size

Related:

• Parameterized Base Class
• Empty Base Optimization