ruby - SKILL.md Agent Skill

name: Ruby slug: ruby version: 1.0.1 description: Write reliable Ruby avoiding mutable string traps, block pitfalls, and metaprogramming bugs. metadata: {"clawdbot":{"emoji":"💎","requires":{"bins":["ruby"]},"os":["linux","darwin","win32"]}}

Topic	File
Mutable strings, object equality	`objects.md`
Proc vs lambda, return behavior	`blocks.md`
Visibility, method_missing	`methods.md`
Array/hash mutation traps	`collections.md`
define_method, eval traps	`metaprogramming.md`
ActiveRecord, N+1, callbacks	`rails.md`

Strings are mutable — s = "hi"; s << "!"; t = s means t also has "!"
== vs equal? vs eql? — == value, equal? identity, eql? hash equality
Default hash value is shared — Hash.new([]) shares same array, use block form
return in proc returns from enclosing method — use lambda for local return
Block variable shadows outer scope — x = 1; [2].each { |x| }; x is still 1 (3.0+)
method_missing without respond_to_missing? — breaks respond_to? checks
private in Ruby is per-object — self.private_method fails, implicit receiver works
||= doesn't work for false/nil distinction — false ||= true replaces false
Frozen string literals — # frozen_string_literal: true makes strings immutable
Symbol#to_proc — &:method_name only works with no-argument methods
rescue => e without type — catches StandardError, not Exception
ensure always runs — even after return, use for cleanup