Go Syntax and interface as parameter to function

Question

I am new to Go programming language and recently encountered the following code:

func (rec *ContactRecord) Less(other interface{}) bool {
  return rec.sortKey.Le         


        

Answer 1

An interface variable can hold values of any type that provides methods with the signatures from the interface declaration. Since interface{} doesn't specify any methods, such a variable can store values of any type.

The method then goes on to use a type assertion to check that other is actually a *ContactRecord value (it will panic otherwise).

You might then ask why the method isn't declared as taking a *ContactRecord argument then. The most likely reason is so that the *ContactRecord type implements some interface with a Less method with that signature.