To create interface use interface keyword, followed by curly braces containing a list of method names, along with any parameters or return values the methods are expected to have. Suppose you define a "rectangle" struct and you want to calculate its area. Golang, how to return in func FROM another func? In the code, we defined a method called (p Person) hello(): func (p Person) hello() {} It is a receiver in Go terms and the syntax looks like this: It's a Go way of creating a method for a struct! If you are not using interfaces, then this doesn’t matter whatsoever and the only benefit you are getting from using a method is syntactic sweetness. A method is a function with a special receiver argument. Type defined in Golang program can have methods associated with it.

The method set of any other type T consists of all methods declared with receiver type T. The method set of the corresponding pointer type *T is the set of all methods declared with receiver *T or T (that is, it also contains the method set of T). // Declare an Interface Type and methods does not have a body type Employee … We talked about functions and structs in the last two sections, but did you ever consider using functions as fields of a struct? A struct (short for "structure") is a collection of data fields with declared data types. The following example shows how we use (or create) the method of the struct. It is that at the time of the call, the receiver is an interface and the function to be called is determined dynamically. Interface describes all the methods of a method set and provides the signatures for each method. Golang has the ability to declare and create own data types by combining one or more types, including both built-in and user-defined types.

There are lots of confusions on how to use interface in Golang, particularly how to implement the methods in interface. Only the non-syntax restriction in the specs text, single, becomes one or more.Multiple return variable declaration probably looks alien at first as well when comming from languages having only a single … The first one uses “value receiver” and the other one uses “pointer receiver”. A method call x.m() is valid if the method set of (the type of) x contains m and the argument list can be assigned to the parameter list of m. If x is addressable and &x’s method set contains m, x.m() is shorthand for (&x).m() This leads to emergent behavior depending on how you define the method, and in particular, the method receiver. Interfaces in Go do not enforce a type to implement methods but interfaces are very powerful tools.