In Go, interfaces are implemented using two main components: interface types and interface values. The Go compiler and runtime work together to manage these components.

1. Interface Types:

• An interface type in Go is a contract that defines a set of methods.
• It specifies the behavior expected from any concrete type that implements the interface.
• An interface type is represented internally as a named struct with two fields:
  • `Type`: Represents the underlying concrete type that implements the interface.
  • `Value`: Represents a pointer to the actual value being stored or referenced.
• The interface type also contains a method table (vtable) that maps the interface methods to the concrete type’s method implementations.

2. Interface Values:

• An interface value in Go is a pair consisting of a concrete value and a corresponding interface type.
• It represents an instance of a type that satisfies the interface.
• An interface value is implemented as a two-word data structure:
  • The first word points to the interface type.
  • The second word points to either the concrete value or a pointer to the concrete value.
• The interface value allows dynamic dispatch of methods based on the underlying concrete type.

Now, let’s discuss the differences between an empty interface and a typed interface:

1. Empty Interface (`interface{}`):

• An empty interface is an interface type with no methods specified.
• It can hold values of any type because any type satisfies an interface with no methods.
• Empty interfaces are commonly used when you need to work with values of unknown or multiple types.
• Since it can hold values of any type, you often need to use type assertions or type switches to extract the underlying value or perform specific operations.

2. Typed Interface:

• A typed interface is an interface type that explicitly specifies one or more methods.
• It defines a contract that a concrete type must fulfill by implementing those methods.
• Typed interfaces are used when you want to define a specific set of behaviors that a type must provide.
• When you use a typed interface, you can directly call the methods defined in the interface without any type assertions or switches.

In summary, Go interfaces are implemented internally using interface types and interface values. The empty interface (`interface{}`) can hold values of any type, while typed interfaces define specific methods that concrete types must implement.