meta_compiler.hpp 3.2 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104
  1. // Copyright (c) 2001-2011 Hartmut Kaiser
  2. // Copyright (c) 2001-2011 Joel de Guzman
  3. //
  4. // Distributed under the Boost Software License, Version 1.0. (See accompanying
  5. // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  6. #if !defined(BOOST_SPIRIT_LEX_META_COMPILER_APR_20_2009_0756PM)
  7. #define BOOST_SPIRIT_LEX_META_COMPILER_APR_20_2009_0756PM
  8. #if defined(_MSC_VER)
  9. #pragma once
  10. #endif
  11. #include <boost/spirit/home/support/meta_compiler.hpp>
  12. #include <boost/spirit/home/lex/domain.hpp>
  13. #include <boost/spirit/home/lex/lexer_type.hpp>
  14. #include <boost/type_traits/remove_reference.hpp>
  15. #include <boost/utility/enable_if.hpp>
  16. namespace boost { namespace spirit
  17. {
  18. template <typename T>
  19. struct use_terminal<lex::domain, T
  20. , typename enable_if<traits::is_lexer<T> >::type> // enables lexers
  21. : mpl::true_ {};
  22. namespace lex
  23. {
  24. template <typename T, typename Modifiers, typename Enable = void>
  25. struct make_primitive // by default, return it as-is
  26. {
  27. typedef T result_type;
  28. template <typename T_>
  29. T_& operator()(T_& val, unused_type) const
  30. {
  31. return val;
  32. }
  33. template <typename T_>
  34. T_ const& operator()(T_ const& val, unused_type) const
  35. {
  36. return val;
  37. }
  38. };
  39. template <typename Tag, typename Elements
  40. , typename Modifiers, typename Enable = void>
  41. struct make_composite;
  42. }
  43. // Lex primitive meta-compiler
  44. template <>
  45. struct make_component<lex::domain, proto::tag::terminal>
  46. {
  47. template <typename Sig>
  48. struct result;
  49. template <typename This, typename Elements, typename Modifiers>
  50. struct result<This(Elements, Modifiers)>
  51. {
  52. typedef typename lex::make_primitive<
  53. typename remove_const<typename Elements::car_type>::type,
  54. typename remove_reference<Modifiers>::type>::result_type
  55. type;
  56. };
  57. template <typename Elements, typename Modifiers>
  58. typename result<make_component(Elements, Modifiers)>::type
  59. operator()(Elements const& elements, Modifiers const& modifiers) const
  60. {
  61. typedef typename remove_const<typename Elements::car_type>::type term;
  62. return lex::make_primitive<term, Modifiers>()(elements.car, modifiers);
  63. }
  64. };
  65. // Lex composite meta-compiler
  66. template <typename Tag>
  67. struct make_component<lex::domain, Tag>
  68. {
  69. template <typename Sig>
  70. struct result;
  71. template <typename This, typename Elements, typename Modifiers>
  72. struct result<This(Elements, Modifiers)>
  73. {
  74. typedef typename
  75. lex::make_composite<Tag, Elements
  76. , typename remove_reference<Modifiers>::type>::result_type
  77. type;
  78. };
  79. template <typename Elements, typename Modifiers>
  80. typename result<make_component(Elements, Modifiers)>::type
  81. operator()(Elements const& elements, Modifiers const& modifiers) const
  82. {
  83. return lex::make_composite<Tag, Elements, Modifiers>()(
  84. elements, modifiers);
  85. }
  86. };
  87. }}
  88. #endif