How to Achieve Reflection-like Functionality in C Using std::map?

How to Call a Function by Its Name (std::string) in C

In C , it's common to use conditional statements to call functions based on a given string. However, this approach can be verbose and inflexible.

Reflection in C

The ability to call a function by its name is known as reflection. Unfortunately, C doesn't natively support this feature.

Workaround Using std::map

One workaround is to create a std::map that associates function names (std::string) with function pointers. For functions with the same prototype, this technique simplifies the process:

<code class="cpp">#include <iostream>
#include <map>

int add(int i, int j) { return i + j; }
int sub(int i, int j) { return i - j; }

typedef int (*FnPtr)(int, int);

int main() {
    // Initialize the map:
    std::map<std::string, FnPtr> myMap;
    myMap["add"] = add;
    myMap["sub"] = sub;

    // Usage:
    std::string s("add");
    int res = myMap[s](2, 3);
    std::cout << res;
}</code>

In this example, myMap[s](2, 3) retrieves the function pointer mapped to the string s and invokes the corresponding function with arguments 2 and 3. The output would be 5.

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