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#include <iostream>
#include <string>
#include <vector>
#include <functional>
using namespace std;
template<typename LHS, typename RHS, template<typename> class Operation>
struct BinExpr;
template<typename RHS>
struct BasicType
{
typedef RHS ObjType;
};
template<typename LHS, typename RHS, template<typename> class Operation>
struct BasicType<BinExpr<LHS, RHS, Operation>>
{
typedef typename BinExpr<LHS, RHS, Operation>::ObjType ObjType;
};
size_t g_binExpr;
template<typename LHS, typename RHS, template <typename> class Operation>
struct BinExpr
{
string d_name;
typedef typename BasicType<RHS>::ObjType ObjType;
typedef typename ObjType::value_type value_type;
LHS const &d_lhs;
RHS const &d_rhs;
BinExpr(LHS const &lhs, RHS const &rhs)
:
d_name("BinExpr" + to_string(g_binExpr++)),
d_lhs(lhs),
d_rhs(rhs)
{
cout << "creating " << d_name <<
" holding " << lhs.d_name << " and " << rhs.d_name << '\n';
}
BinExpr(BinExpr const &other)
:
d_name(other.d_name + "_cc"),
d_lhs(other.d_lhs),
d_rhs(other.d_rhs)
{
cout << "BinExpr copy cons " << d_name << "\n";
}
BinExpr(BinExpr &&tmp)
:
d_name(tmp.d_name + "_mc"),
d_lhs(std::move(tmp.d_lhs)),
d_rhs(std::move(tmp.d_rhs))
{
cout << "BinExpr move cons " << d_name << "\n";
}
size_t size() const
{
return d_lhs.size();
}
value_type operator[](size_t ix) const
{
static Operation<value_type> operation;
cout << "computing " << d_lhs.d_name << '[' << ix << "] + " <<
d_rhs.d_name << '[' << ix << "]\n";
auto ret = operation(d_lhs[ix], d_rhs[ix]);
cout << "computed " << d_lhs.d_name << '[' << ix << "] + " <<
d_rhs.d_name << '[' << ix << "]\n";
return ret;
}
operator ObjType() const
{
ObjType retVal;
for (size_t ix = 0; ix != d_lhs.size(); ++ix)
retVal.push_back((*this)[ix]);
return retVal;
}
};
template<typename LHS, typename RHS>
BinExpr<LHS, RHS, plus> operator+(LHS const &lhs, RHS const &rhs)
{
return BinExpr<LHS, RHS, plus>(lhs, rhs);
}
struct V: public vector<int>
{
string d_name;
static size_t s_nr;
V(string name, int value)
:
vector<int> {value},
d_name(name)
{
cout << "creating V " << d_name << '\n';
}
V()
:
d_name("tmp" + to_string(s_nr++))
{
cout << "creating V " << d_name << '\n';
}
V(V const &other)
:
vector<int>(other),
d_name(other.d_name + "_cc")
{
cout << "V copy cons " << d_name << "\n";
}
V(V &&tmp)
:
vector<int>(std::move(tmp)),
d_name(tmp.d_name + "_mc")
{
cout << "V move cons " << d_name << "\n";
}
V &operator=(V const &other)
{
cout << "assign " << other.d_name << " to " << d_name << '\n';
d_name = other.d_name;
static_cast<vector<int>&>(*this) = other;
return *this;
}
V &operator=(V &&tmp)
{
cout << "moving " << tmp.d_name << " to " << d_name << '\n';
d_name = std::move(tmp.d_name);
static_cast<vector<int>&>(*this) = std::move(tmp);
return *this;
}
};
size_t V::s_nr;
int main()
{
V one{"one", 1};
V two{"two", 2};
V three{"three", 3};
V four{"four", 0};
four = one + two + three + four;
cout << four.d_name << ' ' << four.size() << " first value = " <<
four[0] << '\n';
}
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