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zero.hh
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26 
27 #ifndef MLN_LITERAL_ZERO_HH
28 # define MLN_LITERAL_ZERO_HH
29 
35 
36 # include <mln/core/concept/literal.hh>
37 # include <mln/metal/converts_to.hh>
38 
39 
40 namespace mln
41 {
42 
43  namespace literal
44  {
45 
47  struct zero_t : public Literal<zero_t>
48  {
49  // This default constructor is needed for compilation with gcc
50  // 4.6.0, gcc 4.6.1 and Clang.
51  zero_t();
52 
53  // FIXME: (for the record) Add "friend class Literal<zero_t>;" and a protected ctor.
54 
55  template <typename T>
56  operator const T () const;
57  };
58 
60  extern const zero_t zero;
61 
62 # ifndef MLN_INCLUDE_ONLY
63 
64  inline
66  {
67  }
68 
69  template <typename T>
70  inline
71  zero_t::operator const T () const
72  {
73  mlc_converts_to(int, T)::check();
74  return 0;
75  }
76 
77 # ifndef MLN_WO_GLOBAL_VARS
78 
79  const zero_t zero;
80 
81 # endif // !MLN_WO_GLOBAL_VARS
82 
83 # endif // ! MLN_INCLUDE_ONLY
84 
85  } // end of namespace mln::literal
86 
87 } // end of namespace mln
88 
89 
90 #endif // ! MLN_LITERAL_ZERO_HH