Ruby Development Patterns

Package Manager Detection (CRITICAL)

Before running ANY Ruby commands, detect the package manager:

NEVER use gem install directly when Gemfile exists.

New Project Setup

When scaffolding a new Ruby project, always initialize with Bundler:

bash
1bundle init          # Creates Gemfile
2# Edit Gemfile to add dependencies
3bundle install       # Creates Gemfile.lock

For gem libraries, use bundle gem mylib to scaffold the full structure.

Follow the existing project's Gemfile. Always use bundle exec to run commands.

Project Structure

myproject/
├── lib/                # Source code
│   ├── myproject.rb    # Main entry point
│   └── myproject/      # Namespace directory
│       ├── cli.rb
│       └── core.rb
├── spec/               # RSpec tests (preferred)
│   ├── spec_helper.rb
│   └── myproject/
│       └── core_spec.rb
├── bin/                # Executables
├── Gemfile
├── Gemfile.lock
├── Rakefile
└── Makefile

CLI Structure

Three-layer separation (same principle as Python):

ruby
1# bin/myproject - Minimal bootstrap
2#!/usr/bin/env ruby
3require_relative "../lib/myproject/cli"
4MyProject::CLI.run(ARGV)
5
6# lib/myproject/cli.rb - CLI argument parsing only
7require_relative "core"
8
9module MyProject
10  class CLI
11    def self.run(args)
12      result = Core.process(args.first)
13      puts result
14    end
15  end
16end
17
18# lib/myproject/core.rb - Business logic (testable without CLI)
19module MyProject
20  class Core
21    def self.process(input)
22      # ...
23    end
24  end
25end