Ataraxia through Epoché: [C++] Using Surrogate Call Function for speed up member function name resolution.

Reference:
https://mpark.github.io/programming/2017/08/08/using-killed-the-FUN-on-GCC-5/

Surrogate Call Function:
http://en.cppreference.com/w/cpp/language/overload_resolution#Call_to_a_class_object

sample code:

template <typename Head, typename... Tail>
struct FUN;

// Base case.
template <typename Head>
struct FUN<Head> {
  using F = Head (*)(Head);
  operator F() const;
};

// Recursive case.
template <typename Head, typename... Tail>
struct FUN : FUN<Tail...> {
  using F = Head (*)(Head);
  operator F() const;
};

or just:

template <typename T>
struct FUN_leaf {
  using F = T (*)(T);
  operator F() const;
};

template <typename... Ts>
struct FUN : FUN_leaf<Ts>... {};

Originally(SLOW) using inheritance introduce function name overloading for avoiding hidden ancestor type's function name:

template <typename Head, typename... Tail>
struct FUN;

// Base case.
template <typename Head>
struct FUN<Head> {
  Head operator()(Head) const;
};

// Recursive case.
template <typename Head, typename... Tail>
struct FUN : FUN<Tail...> {
  using FUN<Tail...>::operator();
  Head operator()(Head) const;
};

Ataraxia through Epoché

Sep 15, 2017

[C++] Using Surrogate Call Function for speed up member function name resolution.

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