Boost C++ Libraries: Ticket #933: Can't use BOOST_CLASS_REQUIRES macro

ksvanhorn — Thu, 07 Jun 2001 20:37:06 GMT

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I just tried out the workaround, and it doesn't work --
the second argument needs to be a template, and C++ doesn't
have template typedefs.  So I know of no workaround at all
for this problem.

jsiek — Thu, 07 Jun 2001 20:40:03 GMT

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One option is to added a parameter to the macro for the
namespace.
I'm not all that crazy about that solution. Perhaps there's
a better way...

jsiek — Thu, 07 Jun 2001 21:16:31 GMT

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Here's an alternative to BOOST_CLASS_REQUIRES from Bjarne:
http://www.research.att.com/~bs/bs_faq2.html#constraints
// Here's how I'd adapt it into the boost concept checking
library
namespace boost {
  template <class Concept>
  struct class_requires {
    class_requires() { function_requires<Concept>(); }
  };
} // namespace boost
namespace foo {
  template <class T>
  struct Vector
    : public boost::class_requires<
boost::SGIAssignableConcept<T> >
  {
  };
}// namespace foo

status changed

jsiek — Wed, 19 Oct 2005 20:35:48 GMT

status assigned → closed