Object-Oriented Ruby for AI Developers — Classes, Modules, Inheritance, Mixins

When you start reading Rails code, plain Ruby scripts, or Ruby AI libraries, you hit object-oriented code almost immediately. You see classes. Modules. Inheritance. include . extend . Maybe a service object or two. If you come from Python or JavaScript, Ruby’s object model feels familiar in places and weird in others. The good news: you do not need every edge case to be productive. You need enough to read code, structure code, and avoid writing a mess. Let’s build exactly that. Start with a class A class is a blueprint for objects. Objects hold state and behavior. class PromptTemplate def initialize ( name , template ) @name = name @template = template end def render ( input ) @template . gsub ( "{{input}}" , input ) end end summarizer = PromptTemplate . new ( "summary" , "Summarize this text in 3 bullets: {{input}}" ) puts summarizer . render ( "Ruby is elegant and productive." ) Output: Summarize this text in 3 bullets: Ruby is elegant and productive. A few Ruby basics are doing work