Why distinguish first-class objects from second-class objects and what is this distinction called?

What is a first-class object condition

You can put objects in a collection such as variables or lists. Can be transferred as a function or method parameter It can be used as a return value for a function or method.

There's a lamp.

Among the languages we use a lot, JavaScript, Python is a first-class object language, not c, pascal, or c++.

If you look at JavaScript or Python, you can pass the name of the function as a parameter, and you can use the function within other functions. But if you look at the c, it's impossible It must be passed using a function pointer.

Similarly, even with the return type, Python can be sent freely, but c must also return the pointer.

So in Python, a function or a method is a first-class object, but not in c. It's not a good or bad concept.

However, the characteristics of first-class objects are an important point, especially in functional languages.

Objects that meet certain conditions are called first-class objects.

In a way, something that satisfies the conditions of the First-class citizen seems very common sense and intuitive.

The terms and conditions of the Firm-class Citizen are as follows:

Condition

Simply put, it is understood that it has all the characteristics of an object as a first-class object.

If you say first-class function, you can understand that function is a function that is treated as an object.

It's like a callable object Haha..