Re: [boost] Specializing one of two template parameters?

From: Jens Maurer (Jens.Maurer_at_[hidden])
Date: 2001-07-09 14:47:38

Eric Ford wrote:
> Presently, I'm having a problem specializing a constructor...
> 
> I have the classes
>   template<int Dimension, class TraitsType =
> coordinate_system_traits<Dimension> >  class CartesianCoordinates;
>   template<int Dimension, class TraitsType =
> coordinate_system_traits<Dimension> >  class SphericalCoordinates;
> 
> Included is a constructor using a template for the argument...
> 
>   template<template<> class OtherSystemType>
>   explicit CartesianCoordinates(OtherSystemType<Dimension,TraitsType>
> const& x) throw();
> 
> Now I want to specialize that.  Using pseduo-code, I'd like to do
> something like:
> 
>     template<class TraitsT>
>     CartesianCoordinates<3,TraitsT >(SphericalCoordinate<3,TraitsT>
> const& x)
>     { ...  }

This appears not to be a specialization. The unspecialized constructor
appears to re-use the Dimension and TraitsType from the surrounding
class template.  Your "specialization" tries to have the traits
type as a template parameter in the function template.

You may want to factor common code in a base class and then have
(partially) specialized derived class templates.

Jens Maurer