typedecl

typedecl is a function which, given a type, returns an std::string having the type declaration suitable to be used in a C++ source code.

assert(typedecl<int>() == "int");

using PointerToArrayBiDim = char(*)[3][4];
assert(typedecl<PointerToArrayBiDim>() == "char(*)[3][4]");

using ReferenceToFunction = int(&)(char, int[], ...);
assert(typedecl<ReferenceToFunction>() == "int(&)(char, int*, ...)");

It may be helpful on programs that generate C++ code or to print messages that help debugging template issues.

namedecl

There is also a namedecl function that returns a type declaration with a name. Such a string can be used to declare a variable or to define a type alias with typedef.

assert(namedecl<int>("i") == "int i");
assert(namedecl<char(*)[3][4]>("PoinerToArrayBiDim") == "char(* PoinerToArrayBiDim)[3][4]");
assert(namedecl<int(&)(char, int[], ...)>("callback") == "int(& callback)(char, int*, ...)");

Non-Fundamental Types

typedecl recognizes type constructions with fundamental types (void, nullptr_t, bool, char, int, etc.). Other types such as classes and enums must be registered with the DEFINE_TYPEDECL macro.

class MyClass {
    ...
};

enum MyEnum { ... };

DEFINE_TYPEDECL(MyClass);
DEFINE_TYPEDECL(MyEnum);

void test() {
    assert(typedecl<MyClass>() == "MyClass");
    assert(namedecl<MyClass*[]>("ArrayOfPointersToMyClass") == "MyClass* ArrayOfPointersToMyClass[]");
    assert(typedecl<int(MyEnum&)>() == "int(MyEnum&)");
}

Templates must be registered with the DEFINE_TEMPLATE_TYPEDECL macro. If an alias for a template specialization is registered with DEFINE_TYPEDECL, then the alias is used instead of the name of the template registered with DEFINE_TEMPLATE_TYPEDECL. The types of default template arguments must also be registered.

using MyPair = std::pair<bool, bool>;

DEFINE_TEMPLATE_TYPEDECL(std::pair);
DEFINE_TYPEDECL(MyPair);

DEFINE_TEMPLATE_TYPEDECL(std::vector);
DEFINE_TEMPLATE_TYPEDECL(std::allocator); // std::allocator is used as a default template argument for std::vector

void test() {
    assert((typedecl<std::pair<bool, int>>() == "std::pair<bool, int>"));
    assert((typedecl<std::pair<bool, bool>>() == "MyPair"));

    assert((namedecl<std::pair<bool, int>>("name") == "std::pair<bool, int> name"));
    assert((namedecl<std::pair<bool, bool>>("name") == "MyPair name"));

    assert((typedecl<std::vector<int>>() == "std::vector<int, std::allocator<int>>"));
}

Templates with non-type arguments are not supported.

erdavila/typedecl

typedecl

namedecl

Non-Fundamental Types