Any

A lightweight library for type-erased values in C++. The type-erased Any class allows for storing and manipulating values of any type, with the type of the value being known only at runtime. It includes methods for constructing an Any object, copying the value held by an Any object, and retrieving the type and value of the object.

This library is a case of study and has the same purpose of std::any class introduced in C++17.

Json

A lightweight library to serialize and deserialize Json format in C++.

Dependencies

This library depends on the following libraries:

std: the C++ standard library

Build

To build follow the instructions below:

mkdir build
cd build
cmake ..

Usage

To use the libraries, simply include the Any.h and Json.h header files in your project.

#include "Any.h"
#include "Json.h"
#include <iostream>
#include <vector>
#include <string>
#include <map>

int main()
{

    Any a = 1;
    Any b = string("hello");
    Any c = vector<int>{1, 2, 3};
    Any d = map<string, Any> { 
            {string("a"), 1}, 
            {string("b"), string("hello")}, 
            {string("c"), vector<Any>{1, 2, 3}} 
        };

    cout << a.Get<int>() << endl;
    cout << b.Get<string>() << endl;
    cout << c.Get<vector<int>>().size() << endl;

    for (auto& x : c.Get<vector<int>>())
    { 
        cout << x << " "; 
    } 
    cout << endl;

    // Json format serialization and deserialization example.
    d = Json::Deserialize(Json::Serialize(d));
    for (auto& [key, value] : d.Get<map<string, Any>>())
    {
        try
        {
            auto v = value.Get<int>();
            cout << key << ": " << v << endl;
            continue;
        }
        catch (std::bad_cast& e)
        {
        }

        try
        {
            auto v = value.Get<string>();
            cout << key << ": " << v << endl;
            continue;
        }
        catch (std::bad_cast& e)
        {
        }

        try
        {
            auto v = value.Get<vector<Any>>();
            for (auto& i : v)
                cout << key << ": " << i.Get<int>() << endl;
            continue;
        }
        catch (std::bad_cast& e)
        {
        }
    }

    return 0;
}

Any API

Any()

Constructs an empty Any object.

Any(const T& value)

Constructs an Any object that holds a copy of value.

Any(const Any& other)

Constructs an Any object that holds a copy of the value held by other.

Any& operator=(const Any& other)

Assigns the value held by other to the current Any object.

const std::type_info& Type() const

Returns the type of the value held by the Any object.

template <typename T> T& Get()

If the type of the value held by the Any object is the same as T, returns the value reference. Otherwise, returns generate an exception.

Json API

string Serialize(Any& value)

Returns the string value in json format from an Any object.

Any Deserialize(const std::string& json)

Returns the Any object from a json string format.