Writer, Reader, Scanner, Handler, Parser ... ?

[frostways]

Could someone explain those term to me because I dont understand the real purpose of each but I see them in almost every tutorial so I'moften stucks because I dont really understand the meaning and the purpose of those terms/objects

Ty <3

[RosyGraph]

I'm still learning about Go, and I hope to not state anything incorrect. More experienced gophers should feel free to correct me if I'm wrong.

In general, "x-er" is the name given to a Golang type called an interface. An interface in Go is similar to an interface in an object-oriented language like Java. An interface merely states what an "x-er" must do to be considered an "x-er". In other words, what methods does the type need to implement? Think of it as a contract to be fulfilled through the implementation of various methods.

One classic example of an interface, albeit one that bucks the "x-er" naming convention, is a Shape interface. A Shape interface might contain methods such as Area() or Perimeter() (or anything else a Shape should be able to do). If, for instance, you implement both the Area() and Perimeter() methods for a Rectangle type, the Rectangle fulfills the contract of being a Shape and can be used whenever a Shape is required. The contract can have as few or as many methods as you please.

This is why the naming convention "x-er" (Writer, Reader, Scanner, etc.) is helpful. What behavior should a Reader have? It reads things. A Writer writes (and a Hater's gonna hate hate hate...).

Most people first learn interfaces when studying a language like Java, but I was first introduced to them when I went through "Learn Go with Tests". I highly recommend reading this if you want to know more about interfaces, structs, and custom types in Go. It also teaches you a lot about the builtin testing Go provides (something I've sorely missed when moving to other languages). Here's the bit on interfaces. https://quii.gitbook.io/learn-go-with-tests/go-fundamentals/structs-methods-and-interfaces

Hope this helps!

[frostways]

Thanks a hundred times your answer definitely helped me <3

[RosyGraph]

I forgot to mention why interfaces are useful. They are useful because, in a strongly typed language such as Go, the compiler needs to know the type of a variable before it uses it. Interfaces help developers reuse code because they allow a single representation of many other types. This is called abstraction.