autojanet/skills/understand/languages/ruby.md

Ruby Language Prompt Snippet

Key Concepts

• Blocks/Procs/Lambdas: First-class callable objects; blocks are implicit, procs and lambdas are explicit
• Mixins (include/extend): Share behavior across classes via modules without inheritance
• Metaprogramming: Dynamic method definition (define_method), interception (method_missing)
• Duck Typing: Objects are defined by what they can do, not what class they are
• DSLs: Domain-specific languages built using blocks and metaprogramming (e.g., Rails routes)
• Monkey Patching: Reopening existing classes to add or modify methods at runtime
• Symbols: Immutable, interned strings (:name) used as identifiers and hash keys
• Open Classes: Any class can be reopened and extended at any point in the program
• Enumerable Module: Mixin providing collection methods (map, select, reduce) to any class with each

Import Patterns

• require 'gem_name' — load a gem or standard library module
• require_relative './file' — load a file relative to the current file's directory
• load 'file.rb' — load and re-execute a file (unlike require, does not cache)
• autoload :ClassName, 'path' — lazy loading of constants on first reference

File Patterns

• Gemfile — dependency declarations managed by Bundler
• Rakefile — task definitions (Ruby's make equivalent)
• spec/ — RSpec test directory with *_spec.rb convention
• test/ — Minitest directory with test_*.rb or *_test.rb convention
• config.ru — Rack application entry point for web servers
• lib/ — main source code directory by convention

Common Frameworks

• Rails — Full-stack web framework following convention over configuration
• Sinatra — Minimal DSL for creating web applications quickly
• RSpec — Behavior-driven testing framework with expressive DSL
• Sidekiq — Background job processing using Redis-backed queues
• Grape — REST API micro-framework for Ruby

Example Language Notes

Uses method_missing to dynamically delegate attribute access to the wrapped model object. When a method is not found on the decorator, it falls through to the model, providing transparent delegation without explicit forwarding methods.

Rails relies heavily on convention over configuration — file placement in app/models/, app/controllers/, etc. determines behavior without explicit registration.