cpp-mathmatic-vector/include/math/vector/macro.h

//
//  macro.h
//  vector
//
//  Created by Sam Jaffe on 2/17/24.
//

// Utility Macros
#define COMMA() ,

#define DEFER_RESOLUTION template <bool _ = true>

#define DEFERRED_ENABLE_IF_T(B, ...) std::enable_if_t<B && _, ##__VA_ARGS__>

#define DEFERRED_ENABLE_IF(B, ...)                                             \
  DEFER_RESOLUTION DEFERRED_ENABLE_IF_T(B, ##__VA_ARGS__)

// Repetition Macros for Trivial Codegen
#define REPEAT0(X, div, ...)
#define REPEAT1(X, div, ...) X(0, ##__VA_ARGS__)
#define REPEAT2(X, div, ...)                                                   \
  REPEAT1(X, div, ##__VA_ARGS__) div() X(1, ##__VA_ARGS__)
#define REPEAT3(X, div, ...)                                                   \
  REPEAT2(X, div, ##__VA_ARGS__) div() X(2, ##__VA_ARGS__)
#define REPEAT4(X, div, ...)                                                   \
  REPEAT3(X, div, ##__VA_ARGS__) div() X(3, ##__VA_ARGS__)
#define REPEAT5(X, div, ...)                                                   \
  REPEAT4(X, div, ##__VA_ARGS__) div() X(4, ##__VA_ARGS__)

#define REPEAT(N, X, div, ...) REPEAT##N(X, div, ##__VA_ARGS__)

#define ARGN(N, ...) __VA_ARGS__ arg##N

// Vector Concept Macros
#define VECTOR_ENABLE_IF_LT_N(index, expr)                                     \
  DEFERRED_ENABLE_IF(std::size_t(index) < N, expr)

#define VECTOR_ENABLE_IF_EQ_N(index, t, n)                                     \
  DEFERRED_ENABLE_IF(std::size_t(index) == N, vector<t, n>)

#define VECTOR_ENABLE_IF_EQ_T(_type, t, n)                                     \
  std::enable_if_t<std::is_same_v<_type, t>, vector<t, n>>

#define VECTOR_DISABLE_IF_VECTOR(_type, t, n)                                  \
  std::enable_if_t<!is_vector_v<_type>, vector<t, n>>

// Vector Access/Iteration Macros
#define VECTOR_ACCESS_FN(name, i)                                              \
  VECTOR_ENABLE_IF_LT_N(i, value_type const &) name() const {                  \
    return _data[i];                                                           \
  }                                                                            \
  VECTOR_ENABLE_IF_LT_N(i, value_type &) name() { return _data[i]; }

#define VECTOR_FOR_EACH_RANGE(var, end)                                        \
  for (std::size_t var = 0; var < end; ++var)
#define VECTOR_FOR_EACH(var) VECTOR_FOR_EACH_RANGE(var, N)

#define VECTOR_CTOR_N_ARGS(N_IN)                                               \
  DEFER_RESOLUTION vector(REPEAT(N_IN, ARGN, COMMA, T),                        \
                          DEFERRED_ENABLE_IF_T(N_IN == N, bool) = true)        \
      : vector(std::array{REPEAT(N_IN, ARGN, COMMA)})