Methods Versus Functions

Differences between a function and a method

A function has the variable as a parameter:

Function1(recv)

A method is called on the variable:

recv.Method1()

A method can change the values (or the state) of the receiver variable provided this is a pointer, just as is the case with functions (a function can also change the state of its parameter when this is passed as a pointer: call by reference).

Note: Don’t forget the ( ) after Method1, or you get the compiler error: method recv.Method1 is not an expression, must be called.

The receiver must have an explicit name, and this name must be used in the method. receiver-type is called the (receiver) base type; this type must be declared within the same package as all of its methods. In Go, the methods attached to a (receiver) type are not written inside of the structure, as is the case with classes; the coupling is much loose: the receiver establishes the association between method and type.

Methods are not mixed with the data definition (the structs). They are orthogonal to types; representation (data) and behavior (methods) are independent.