2.5 KiB
2.5 KiB
nameof() c++11
C++ alternative to nameof operator.
| Linux/OSX | Windows |
|---|---|
 |
Used to obtain the simple name of a variable, type, function. Before, you had to use string literals to refer to definitions, which is brittle when renaming code elements because tools do not know to check these string literals.
A nameof expression has this form:
std::cout << NAMEOF(person.address.zip_code) << std::endl; // prints "zip_code"
Features
- Simple name
- C++11
- Header-only
- Dependency-free
- Compile-time
- Compilation check
Example & Key Use Cases
- Name of a variable, function and etc
NAMEOF(someVar) -> "someVar"
NAMEOF(someVar.SomeField) -> "SomeField"
NAMEOF(someVar.SomeMethod1()) -> "SomeMethod1()"
NAMEOF(&SomeStruct::SomeMethod2) -> "SomeMethod2"
- Name of enum
NAMEOF(SomeEnum::RED) -> "RED"
NAMEOF(SomeEnum::GREEN) -> "GREEN"
- Name of type
NAMEOF_TYPE(int[]) -> "int[]"
NAMEOF_TYPE(std::string) -> "string"
- Constexpr
void f() {
int i;
constexpr auto constexpr_work_fine = NAMEOF(i); -> "i"
}
- Compilation check
void f() {
int i;
NAMEOF(i); -> "i"
NAMEOF(iii); -> error identifier "iii" is undefined
NAMEOF_TYPE(std::stringgg) -> error namespace "std" has no member "stringgg"
}
- Validate parameters
void f(char* s) {
if (s == nullptr)
throw std::invalid_argument(NAMEOF(s));
}
- Serialization, for example json:
void to_json(json& j, const person& p) {
j = json{{NAMEOF(p.name), p.name},
{NAMEOF(p.address), p.address},
{NAMEOF(p.age), p.age}};
}
void from_json(const json& j, person& p) {
p.name = j.at(NAMEOF(p.name));
p.address = j.at(NAMEOF(p.address));
p.age = j.at(NAMEOF(p.age));
}
- Logging
void f() {
Log(NAMEOF(f), " method entry");
}
Remarks
If you need to get the fully-qualified name, you can use the NAMEOF_FULL(). For example:
NAMEOF_FULL(someVar.SomeField) -> "someVar.SomeField"
NAMEOF_FULL(&SomeStruct::SomeMethod2) -> "&SomeStruct::SomeMethod2"
NAMEOF_TYPE_FULL(std::string) -> "std::string"