Casting back to more specialised interface

Question

I\'m writing a game in go. In C++ I would store all my entity classes in an array of the BaseEntity class. If an entity needed to move about in the world it would be a PhysEntit

Answer 1

Specifically, the Go "interface" type has the information on what the object really was, that was passed by interface, so casting it is much cheaper than a C++ dynamic_cast or the equivalent java test-and-cast.

Answer 2

Use a type assertion. For example,

original, ok := entity.(PhysEntity)
if ok {
    println(original.b())
}