Compiletime Metaprogramming in C++ in P1717R0
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< cpp | experimental
Contents |
[edit] Introduction
This is based on P0712.
template<typename... Types>
class tuple {
consteval {
int counter = 0;
for... (meta::info type : reflexpr(Types)) {
auto fragment = __fragment struct {
typename(type) unqualid("element_", counter);
};
-> fragment;
++counter;
}
}
};
tuple<bool, char, int> tup;
same as
template<typename... Types>
class tuple {
bool element0;
char element1;
int element2;
};
[edit] consteval{ ... }
the stuff filled in it is called metaprogram. It is executed where they appear in the translation unit.
[edit] typename( meta::info )
The typename of a reflection of a type can be gotten by typename operator.
[edit] unqualid
This operator makes a new unqualifiedid. It takes a few arguments, which are concatenated to form the new identifier.
[edit] ->fragment
This operator sends a request to the compiler. Compiler would inject the fragment.
[edit] __fragment
[edit] Class fragments
TODO:
[edit] Namespace Fragments
TODO:
[edit] Enum Fragment
TODO:
[edit] Block Fragments
TODO:
[edit] Parameterizing Fragments
TODO:
[edit] Nonlocal dependencies
TODO:
[edit] Parameter Injection
TODO:
[edit] Metaclasses
TODO:
