Interpreter

This design pattern may seem very simple or very hard, based on how much background you have in computer science. Some books that discuss classical software design patterns even decide to omit it altogether or put it somewhere at the end, for curious readers only.

The reason behind this is that the Interpreter design pattern deals with translating specific languages. But why would we need that? Don't we have compilers to do that anyway?

We need to go deeper

All developers have to speak many languages or sub-languages. Even as regular developers, we use more than one language. Think of tools that build your projects, such as Maven or Gradle. You can consider their configuration files and build scripts as languages with specific grammar. If you put elements out of order, your project won't be built correctly. This is because such projects have interpreters to analyze configuration files and act upon them.

Other examples are query languages, whether...