concept_def.hpp 3.1 KB

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  1. // Copyright David Abrahams 2006. Distributed under the Boost
  2. // Software License, Version 1.0. (See accompanying
  3. // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  4. #ifndef BOOST_CONCEPT_DETAIL_CONCEPT_DEF_DWA200651_HPP
  5. # define BOOST_CONCEPT_DETAIL_CONCEPT_DEF_DWA200651_HPP
  6. # include <boost/preprocessor/seq/for_each_i.hpp>
  7. # include <boost/preprocessor/seq/enum.hpp>
  8. # include <boost/preprocessor/comma_if.hpp>
  9. # include <boost/preprocessor/cat.hpp>
  10. #endif // BOOST_CONCEPT_DETAIL_CONCEPT_DEF_DWA200651_HPP
  11. // BOOST_concept(SomeName, (p1)(p2)...(pN))
  12. //
  13. // Expands to "template <class p1, class p2, ...class pN> struct SomeName"
  14. //
  15. // Also defines an equivalent SomeNameConcept for backward compatibility.
  16. // Maybe in the next release we can kill off the "Concept" suffix for good.
  17. #if BOOST_WORKAROUND(__GNUC__, <= 3)
  18. # define BOOST_concept(name, params) \
  19. template < BOOST_PP_SEQ_FOR_EACH_I(BOOST_CONCEPT_typename,~,params) > \
  20. struct name; /* forward declaration */ \
  21. \
  22. template < BOOST_PP_SEQ_FOR_EACH_I(BOOST_CONCEPT_typename,~,params) > \
  23. struct BOOST_PP_CAT(name,Concept) \
  24. : name< BOOST_PP_SEQ_ENUM(params) > \
  25. { \
  26. /* at least 2.96 and 3.4.3 both need this */ \
  27. BOOST_PP_CAT(name,Concept)(); \
  28. }; \
  29. \
  30. template < BOOST_PP_SEQ_FOR_EACH_I(BOOST_CONCEPT_typename,~,params) > \
  31. struct name
  32. #else
  33. # define BOOST_concept(name, params) \
  34. template < BOOST_PP_SEQ_FOR_EACH_I(BOOST_CONCEPT_typename,~,params) > \
  35. struct name; /* forward declaration */ \
  36. \
  37. template < BOOST_PP_SEQ_FOR_EACH_I(BOOST_CONCEPT_typename,~,params) > \
  38. struct BOOST_PP_CAT(name,Concept) \
  39. : name< BOOST_PP_SEQ_ENUM(params) > \
  40. { \
  41. }; \
  42. \
  43. template < BOOST_PP_SEQ_FOR_EACH_I(BOOST_CONCEPT_typename,~,params) > \
  44. struct name
  45. #endif
  46. // Helper for BOOST_concept, above.
  47. # define BOOST_CONCEPT_typename(r, ignored, index, t) \
  48. BOOST_PP_COMMA_IF(index) typename t