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Document number: N3749

Date: 2013-08-31

Constexpr Library Additions: functional

by Marshall Clow

Excerpt:

I propose that we make the following change:

template <class T = void> struct less {
  typedef T first_argument_type;
  typedef T second_argument_type;
  typedef bool result_type;

  constexpr bool operator()(const T& x, const T& y) const { return x < y; }

  };

This will allow people to use less<T>{}(x,y) at compile time.

This should also apply to all the relational operators (less, greater, less_equal, greater_equal, not_equal_to, equal_to), the arithmetic operators (plus, minus, multiplies, divides, modulus, negates), the bit manipulations (bit_and, bit_or, bit_xor, bit_not) and the negators (unary_negate, binary_negate, no1, not2).