Interface

1. Interface is a custom type that specifies a set of one or more method signature.
2. Interfaces are abstract, it is not possible to instantiate an Interface
3. Though, it is possible to create a variable whose type is that of Interface, which can be assigned a value of any concrete type which has methods required by interface.
4. interface{} type is interface that species empty set of methods.
5. Every value satisfies interface{} type, as it will have its own set of methods which includes empty set of methods. So, interface{} type can be used for all values.

Interface Values

1. A value of an Inetrface Type, or interface value has two components. a. dynamic type --> concrete type b. dynamic value --> value of that concrete type

Type Assertions

1. Type assertion is an operation performed on Interfaces.

2. It takes the form of x.(T) where x is expression of interface type and T is a type called "Asserted Type"

3. A type assertion checks whether the dynamic type of its operand matches the asserted type.

4. t := i.(T) i checks if i implements interface T and assigns the underlying concrete value of i to t, in case it does not it panics.

5. t, ok := i.(T), if T is not an interface, it checks whether dynamic value of i is identical to t and assigns t the concrete value of i