Overview

Go doesn't support function overloading!

Methods

• Methods are known as receivers or receiver functions in Go
• Receivers can be defined on any user-defined type in Go
• You can define multiple receivers with same name but on different receiver types, within a package
• They need to be defined in the same package as the type is defined in
• Getters & Setters are anti-patterns in Go

Value receivers

• func (<varName> <receiverType>) <funcNameA>() { ... }
  • Eg. func (f MyFloat) Abs() float64 { ... }
• There is no this or self keyword in go, which could give you a hold of the variable on which you are dispatching a receiver.
  • They are instead passed in to the receiver, the same way you have arguments to a function

Pointer receivers

• func (<varName> *<receiverType>) <funcNameB>() { ... }
  • Eg. func (v *Vertex) Scale() float64 { ... }
• Pointer receivers can help in:
  • Avoiding copy of a large-ish struct variable
  • Update fields of a struct variable
  • Useful for dispatching even on nil values
• Same as fields, don't need any dereferencing to invoke

Value & Pointer types

• The value & pointer receivers can be dispatched interchangeably:

  • var v <receiverType>
    • v.funcNameA() & v.funcNameB()
  • p := &v
    • p.funcNameA() & p.funcNameB()

• Eg.

  value receiver: (v Vertex) Abs

  pointer receiver: (v *Vertex) Scale

  value: var vertex Vertex

  pointer: var p *Vertex

  vertex.Abs()
  vertex.Scale()

  p.Abs()
  p.Scale()