TypeList.cpp

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  @file TypeList.cpp
  @brief Examples as a compile-time unit test of metaprogramming utilities
 
  Paul Licameli
 
**********************************************************************/
#include "TypeList.h"
#include <array>
 
// Enough examples to test compilation of all the templates
namespace { using namespace TypeList; using namespace std;
 
using Example = List<int, double>;
 
static_assert(Null_v<Nil>);
static_assert(!Null_v<Example>);
 
static_assert(0 == Length_v<Nil>);
static_assert(2 == Length_v<Example>);
 
static_assert(is_same_v<int, Head_t<Example>>);
 
// These compile even though Head_t<Nil> does not
using Unused = Head<Nil>;
static_assert(is_same_v<int, Head_t<conditional_t<true, Example, Nil>>>);
template <typename T> struct ShortCircuiting
   : Head<conditional_t<Null_v<T>, Example, T>>{};
static_assert(is_same_v<int, ShortCircuiting<Nil>::type>);
static_assert(is_same_v<double, ShortCircuiting<List<double>>::type>);
 
static_assert(is_same_v<List<double>, Tail_t<Example>>);
 
static_assert(is_same_v<int, First_t<Example>>);
static_assert(is_same_v<double, Second_t<Example>>);
 
static_assert(is_same_v<Example, Cons_t<int, Cons_t<double, Nil>>>);
static_assert(is_same_v<Example, PushFront_t<PushFront_t<Nil, double>, int>>);
static_assert(is_same_v<Example, PushBack_t<PushBack_t<Nil, int>, double>>);
 
static_assert(is_same_v<Nil, NonEmptyTails_t<Nil>>);
static_assert(is_same_v<List<Example, List<double>>, NonEmptyTails_t<Example>>);
 
static_assert(is_same_v<List<Nil>, Tails_t<Nil>>);
static_assert(is_same_v<List<Example, List<double>, Nil>, Tails_t<Example>>);
 
static_assert(is_same_v<double, Last_t<Example>>);
static_assert(is_same_v<List<int>, ButLast_t<Example>>);
 
static_assert(is_same_v<Example, Map_t<Identity, Example>>);
static_assert(is_same_v<List<const int, const double>,
   Map_t<Fn<add_const_t>, Example>>);
static_assert(is_same_v<List<const int&, const double &>,
   Map_t<Fn<add_lvalue_reference_t, add_const_t>, Example>>);
static_assert(is_same_v<List<const int*&, const double *&>,
   Map_t<
      Fn<add_lvalue_reference_t, add_pointer_t, add_const_t>,
      Example>>);
static_assert(is_same_v<List<int *const &, double *const &>,
   Map_t<
      Compose<
         Fn<add_lvalue_reference_t>,
         Fn<add_const_t, add_pointer_t>>,
      Example>>);
 
static_assert(is_same_v<Nil, MapList_t<Fn<Length_t>, Nil>>);
static_assert(is_same_v<
   List<integral_constant<size_t, 2>, integral_constant<size_t, 1>>,
   MapList_t<Fn<Length_t>, Example>>);
 
static_assert(is_same_v<tuple<int, double>, Apply_t<tuple, Example>>);
static_assert(is_same_v<tuple<const int, const double>,
   Apply_t<tuple, Map_t<Fn<add_const_t>, Example>>>);
 
static_assert(is_same_v<Example, Bind_t<tuple<int, double>>>);
static_assert(is_same_v<Example, Bind_t<pair<int, double>>>);
static_assert(is_same_v<List<int, int>, Bind_t<array<int, 2>>>);
 
static_assert(is_same_v<Nil, Append_t<>>);
static_assert(is_same_v<Example, Append_t<Example>>);
static_assert(is_same_v<List<int, double, char>,
   Append_t<Example, List<char>>>);
 
static_assert(is_same_v<List<Example, List<int>>,
   LeftFoldList_t<Cons_t, Example, Nil>>);
 
static_assert(is_same_v<List<Example, List<double>>,
   RightFoldList_t<Cons_t, Example, Nil>>);
 
static_assert(is_same_v<List<double, int>, Reverse_t<Example>>);
 
static_assert(is_same_v<const int, Call_t<MaybeConst<true>, int>>);
static_assert(is_same_v<int, Call_t<MaybeConst<false>, int>>);
 
static_assert(is_same_v<List<const int, const double>,
   MapConst_t<true, Example>>);
static_assert(is_same_v<Example, MapConst_t<false, Example>>);
 
static_assert(Is_v<Fn<Null>, Nil>);
static_assert(!Is_v<Fn<Null>, Example>);
static_assert(!Is_v<Not<Fn<Null>>, Nil>);
static_assert(Is_v<Not<Fn<Null>>, Example>);
 
using HeadIsInt = Compose<Bind1st<is_same, int>, Fn<Head_t>>;
static_assert(Is_v<HeadIsInt, Example>);
// static_assert(!Is_v<HeadIsInt, Nil>); // won't compile
 
using StartsWithInt = And<Not<Fn<Null>>, HeadIsInt>;
static_assert(!Is_v<StartsWithInt, Nil>);
static_assert(Is_v<StartsWithInt, Example>);
 
using NullOrStartsWithInt = Or<Fn<Null>, HeadIsInt>;
static_assert(Is_v<NullOrStartsWithInt, Nil>);
static_assert(Is_v<NullOrStartsWithInt, Example>);
 
static_assert(Every_v<Fn<is_arithmetic>, Example>);
static_assert(is_base_of_v<true_type, Every<Fn<is_arithmetic>, Example>>);
static_assert(!Every_v<Fn<is_integral>, Example>);
static_assert(is_base_of_v<is_integral<double>,
   Every<Fn<is_integral>, Example>>);
 
static_assert(Some_v<Fn<is_integral>, Example>);
static_assert(is_base_of_v<is_integral<int>,
   Some<Fn<is_integral>, Example>>);
static_assert(!Some_v<Fn<is_void>, Example>);
static_assert(is_base_of_v<false_type, Some<Fn<is_void>, Example>>);
 
static_assert(NotEvery_v<Fn<is_floating_point>, Example>);
static_assert(NotAny_v<Fn<is_void>, Example>);
 
static_assert(!In_v<void, Example>);
static_assert(In_v<int, Example>);
 
struct B {};
struct D : B {};
 
static_assert(HasBaseIn_v<D, List<B>>);
static_assert(HasBaseIn_v<D, List<D>>);
static_assert(HasBaseIn_v<B, List<B>>);
static_assert(!HasBaseIn_v<B, List<D>>);
static_assert(HasBaseIn_v<B, List<B, D>>);
 
static_assert(is_same_v<List<Nil, Example>,
   StablePartition_t<Fn<is_void>, Example>>);
static_assert(is_same_v<List<List<int>, List<double>>,
   StablePartition_t<Fn<is_integral>, Example>>);
static_assert(is_same_v<List<Example, Nil>,
   StablePartition_t<Fn<is_arithmetic>, Example>>);
 
static_assert(is_same_v<Nil, Filter_t<Fn<is_void>, Example>>);
static_assert(is_same_v<List<int>, Filter_t<Fn<is_integral>, Example>>);
static_assert(is_same_v<Example, Filter_t<Fn<is_arithmetic>, Example>>);
 
using Example2 = Cons_t<unsigned, Example>;
static_assert(is_same_v<List<unsigned>,
   Filter_t<And<Not<Fn<is_signed>>, Fn<is_integral>>, Example2>>);
static_assert(is_same_v<List<unsigned, double>,
   Filter_t<Or<Not<Fn<is_signed>>, Fn<is_floating_point>>, Example2>>);
 
// To do: more cases
}