Repetitive data type while reading

[lvkins]

Is this possible to get a value with auto data type detection?

Consider following:

struct Test {
       std::string value;
       int32_t index;
       std::vector<int32_t> acro;
}

To parse these, we need to do the following:

void from_json(const json& j, Files::Chapters::Test& p) {
    p.value = j.at("value").get<std::string>();
    p.index = j.at("index").get<int32_t>();
    p.acro = j.at("acro").get<std::vector<int32_t>>();
}

Thats quite a boilerplate.

We can also do this:

void from_json(const json& j, Files::Chapters::Test& p) {
    p.value = j.at("value").get<typeof(p.value)>();
    p.index = j.at("index").get<typeof(p.index)>();
    p.acro = j.at("acro").get<typeof(p.acro)>();
}

As you can see, this is repetitive thus redudant. Can't we simply get value with the data type of a object we assign to?

[nlohmann]

You can at least do this:

void from_json(const json& j, Test& p) {
    p.value = j.at("value");
    p.index = j.at("index");
    p.acro = j.at("acro").get<std::vector<int32_t>>();
}

For the vector, there seems to be confusion. Are the first two lines what you want?

[lvkins]

Yep, good for common data types.

Thanks 👍