Solidity Tutorial: all about Modifiers

Modifiers are analog to the decorator pattern (source: https://refactoring.guru/design-patterns/decorator)

In Solidity, Modifiers express what actions are occurring in a declarative and readable manner. They are similar to the decorator pattern used in Object Oriented Programming.

What is exactly a Modifier in Solidity ?

The Solidity documentation define a modifier as follow:

A function modifier is a compile-time…