fork download

#include <iostream>
#include <map>
 
using namespace std;
 
class Type
{
public:
    Type() {}
 
    virtual void setValue(std::string val) = 0;
};
 
class Integer : public Type
{
public:
    Integer() : Type() { value = 0; }
    virtual void setValue(std::string val) {
        value = stoi(val);
    }
    int value;
};
 
class String : public Type
{
public:
    String() : Type() { }
    virtual void setValue(std::string val) {
        value = val;
    }
    string value;
};
 
class A
{
public:
    A() { };
 
    static map<string, Type* A::*> getDataBindings() {
        map<string, Type* A::*> datas;
        datas["name"] = &A::p_name;
        datas["age"] = &A::p_age;
    }
 
    Integer p_age;
    String p_name;
};
 
int main()
{
	// here I can store my data bindings once and for all, avoiding to call
	// getDataBindings for each object of class A.
    map<string, Type* A::*> dataBindingsForA = A::getDataBindings();
 
    A a1, a2, a3, a4, a5;
 
    // here you could say "use p_name/p_age directly" but in my use case i need
    // to bind the variables to actual names (think SQL)
    a1.*dataBindingsForA["name"]->setValue("John Doe 1");
    a1.*dataBindingsForA["age"]->setValue("10");
 
    a2.*dataBindingsForA["name"]->setValue("John Doe 2");
    a2.*dataBindingsForA["age"]->setValue("20");
 
    a3.*dataBindingsForA["name"]->setValue("John Doe 3");
    a3.*dataBindingsForA["age"]->setValue("30");
 
    a4.*dataBindingsForA["name"]->setValue("John Doe 4");
    a4.*dataBindingsForA["age"]->setValue("40");
 
    a5.*dataBindingsForA["name"]->setValue("John Doe 5");
    a5.*dataBindingsForA["age"]->setValue("50");
 
    return 0;
}

prog.cpp: In static member function 'static std::map<std::basic_string<char>, Type* A::*> A::getDataBindings()':
prog.cpp:41:23: error: cannot convert 'String A::*' to 'std::map<std::basic_string<char>, Type* A::*>::mapped_type {aka Type* A::*}' in assignment
         datas["name"] = &A::p_name;
                       ^
prog.cpp:42:22: error: cannot convert 'Integer A::*' to 'std::map<std::basic_string<char>, Type* A::*>::mapped_type {aka Type* A::*}' in assignment
         datas["age"] = &A::p_age;
                      ^
prog.cpp: In function 'int main()':
prog.cpp:59:33: error: base operand of '->' is not a pointer
     a1.*dataBindingsForA["name"]->setValue("John Doe 1");
                                 ^
prog.cpp:60:32: error: base operand of '->' is not a pointer
     a1.*dataBindingsForA["age"]->setValue("10");
                                ^
prog.cpp:62:33: error: base operand of '->' is not a pointer
     a2.*dataBindingsForA["name"]->setValue("John Doe 2");
                                 ^
prog.cpp:63:32: error: base operand of '->' is not a pointer
     a2.*dataBindingsForA["age"]->setValue("20");
                                ^
prog.cpp:65:33: error: base operand of '->' is not a pointer
     a3.*dataBindingsForA["name"]->setValue("John Doe 3");
                                 ^
prog.cpp:66:32: error: base operand of '->' is not a pointer
     a3.*dataBindingsForA["age"]->setValue("30");
                                ^
prog.cpp:68:33: error: base operand of '->' is not a pointer
     a4.*dataBindingsForA["name"]->setValue("John Doe 4");
                                 ^
prog.cpp:69:32: error: base operand of '->' is not a pointer
     a4.*dataBindingsForA["age"]->setValue("40");
                                ^
prog.cpp:71:33: error: base operand of '->' is not a pointer
     a5.*dataBindingsForA["name"]->setValue("John Doe 5");
                                 ^
prog.cpp:72:32: error: base operand of '->' is not a pointer
     a5.*dataBindingsForA["age"]->setValue("50");
                                ^

Standard output is empty