Function relu

sample/relu.cpp:4–13

#include <iostream>

constexpr double relu(double value)
{
  using namespace matchit;
  return match(value)(
      // clang-format off
        pattern | (_ >= 0) = expr(value),
        pattern | _        = expr(0)
      // clang-format on
  );
}

static_assert(relu(5) == 5);
static_assert(relu(-5) == 0);