I want to create functions with dot operator like these:

Regedit.Key.Create();
Regedit.Value.Create();
Regedit.Value.Read();

How can I do that?

CodePudding user response：

In C you will need to write getter functions, and then the syntax becomes editor.Key().Create();

class Key
{
public:
    Key() = default;
    ~Key() = default;

    void Create() 
    {
    };
};

class RegEdit
{
public:
    // in C   you need to use a getter function 
    Key& key() 
    {
        return m_key;
    }

private:
    Key m_key;
};

int main()
{
    RegEdit editor;
    editor.key().Create();

    return 0;
}

CodePudding user response：

For Regedit.Key.Create(); to be a valid C instruction, some conditions are required:

• Regedit must be an object (ie an instance of a C class)
• Key must be a member attribute of Regedit
• that attribute must also be an object
• Create must be a method of that object

Here is an example code meeting those conditions, where RegAccessor is the class for Regedit and Selector is the class for Regedit.Key:

#include <iostream>

class Selector {
public:
    enum class Type {
        Key,
        Value
    };
    friend std::ostream& operator << (std::ostream& out, const Type& type) {
        const char *name;
        switch (type) {
            case Type::Key: name = "Key"; break;
            case Type::Value: name="Value"; break;
            default: name="Unknown";
        }
        out << name;
        return out;
    }
    
    Selector(Type type): type(type) {};
    
    void Create() {
        // write more relevant code here...
        std::cout << "Create " << type << " called\n";
    }
    void Read() {
         // write more relevant code here...
       std::cout << "Read " << type << " called\n";
    }

private:
    Type type;
};



class RegAccessor {
public:
    Selector Key = Selector::Type::Key;
    Selector Value = Selector::Type::Value;
};

int main(int argc, char **argv)
{
    RegAccessor Regedit;
    // here is exactly your example code
    Regedit.Key.Create();
    Regedit.Value.Create();
    Regedit.Value.Read();
    return 0;
}