Have you ever wonder how the below TcpListener Code run infinitely looking for new connections/clients.
Code:
When you run this below program with a Rust compiler or Cargo run, you will see that the program is not ending. How ?
As you noticed , the for loop doesn't have a explicit condition to exit. As far as the Iterator can return values, the "for loop" construct execute the statements inside the body. The Iterators can behave like an infinite loop.But can return "None"(which can be used to exit from "for") , or can return Some values from next method .
Ok..we understood that there is something called Iterator which can yield for values infinite.
But where is the Iterator here ?
When you look at the TcpListener , it is just a struct. But it has one particular method which implements Iterator trait.
The connections can be accepted from TcpListener through a struct called std::net::Incoming which is an Iterator.It is hidden(abstracted) behind the method incoming in this case. As I said earlier Iterators can yield and ask for values infinite times.
Iterator Trait is implemented on the struct "Incoming"
As you noticed the next method on the Iterator is not going to end. It just keep iterate as far as we are calling incoming method.
Incoming struct accepts connections of TcpListener:
Incoming implementing Iterator trait:
