#include <cassert>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include <string>
#include <variant>
#include <vector>

struct Variable_Error : public std::runtime_error
{ using std::runtime_error::runtime_error; };

// Implement Variable here

int main()
{
    Variable v1 { 3.0 };
    Variable v2 { 5.0 };

    {
        std::ostringstream oss { };
        (v1 + v2).print(oss);

        assert( oss.str() == "8" );
    }

    // ensure that v1.size() throws a Variable_Error exception
    try { v1.size(); assert(false); }
    catch (Variable_Error& error) { }
    catch (...) { assert(false); }

    {
        std::ostringstream oss { };
        (v2 - v1).print(oss);

        assert( oss.str() == "2" );
    }

    v2 = "my text";
    assert( v2.size() == 7 );

    // ensure that variables of different types throws a Variable_Error exception
    try { (v1 + v2); assert(false); }
    catch (Variable_Error& error) { }
    catch (...) { assert(false); }

    // operator- should not work for anyting but numbers
    try { (v2 - v2); assert(false); }
    catch (Variable_Error& error) { }
    catch (...) { assert(false); }

    Variable v3 { { v1, v2 } };
    assert( v3.size() == 2 );

    {
        std::ostringstream oss { };
        v3.print(oss);

        assert( oss.str() == "[ 3 \"my text\" ]" );
    }

    v1 = { v1, v2, v3 };
    assert( v1.size() == 3 );

    {
        std::ostringstream oss { };
        v1.print(oss);

        assert( oss.str() == "[ 3 \"my text\" [ 3 \"my text\" ] ]" );
    }
}