Ruby

Skill: ruby

What I do

I provide Ruby-specific expertise: idiomatic patterns, Rails conventions, gem ecosystem knowledge, and best practices for writing clean, maintainable Ruby code.

When to use me

• Writing Ruby code (any context)
• Designing Ruby APIs or designing DSLs
• Working with Rails applications
• Choosing and integrating gems
• Refactoring Ruby for clarity and performance

Core principles

1. Convention over configuration - Follow Rails conventions, don't override them
2. DRY (Don't Repeat Yourself) - Extract logic to methods, concerns, and services
3. Ruby is for humans - Readable, expressive code beats clever code
4. Blocks and iterators - Core Ruby strength, use them idiomatically
5. Frozen strings - Use frozen_string_literal: true at file top

Patterns & examples

Idiomatic iteration:

# ✅ Correct: use each, map, select with blocks
[1, 2, 3].each { |n| puts n }
numbers.map { |n| n * 2 }
items.select { |i| i.valid? }

# ❌ Wrong: C-style for loops
for i in 0..items.length-1
  puts items[i]
end

Rails service pattern:

# ✅ Correct: Extract business logic to service
class CreateOrderService
  def initialize(user, items)
    @user = user
    @items = items
  end
  
  def call
    Order.create(user: @user, items: @items)
  end
end

# In controller:
order = CreateOrderService.new(@user, params[:items]).call

Frozen string literals:

# ✅ Correct: frozen string at file top
# frozen_string_literal: true

class User
  ROLE = 'admin'  # frozen by default now
end

# ❌ Wrong: mutable strings in constants
ROLE = 'admin'.dup  # wasteful, implies mutation

Anti-patterns to avoid

• ❌ Monolithic controller actions (extract to services)
• ❌ Complex view logic (move to helpers or view components)
• ❌ Ignoring n+1 queries (use includes, eager_load)
• ❌ Exception handling as control flow (use dig, try, explicit checks)
• ❌ Mutable defaults in arguments (def foo(items=[])—use nil and initialize in body)

KB Reference

~/vaults/baphled/3. Resources/Knowledge Base/AI Development System/Skills/Languages/Ruby.md

Related skills

• clean-code - SOLID principles in Ruby
• bdd-workflow - Test-driven development workflow
• rspec-testing - RSpec BDD testing framework
• design-patterns - Common patterns in Ruby