api: YAML JSON TOON Database
version: 1.0.0
format: json
dataset:
  id: 50
  slug: ruby-language-essentials
  title: Ruby Language Essentials
  description: "Core Ruby programming concepts: blocks, procs, lambdas, metaprogramming, gems, Rails conventions, and Ruby idioms."
  summary: "Ruby's essential language concepts: blocks, procs, lambdas, metaprogramming, mixins, Enumerable, singleton methods and method_missing, each with type, syntax, a description and an example."
  use_when:
    - You are learning Ruby's distinctive features or reading Rails-style code.
    - You need the difference between blocks, procs and lambdas.
  caveats:
    - Metaprogramming is powerful but makes code harder to trace; use it sparingly.
    - Behavior can differ slightly between Ruby versions; confirm the version in use.
  related:
    - language-comparison-2026
    - python-builtins
    - behavioral-design-patterns
    - javascript-es6-features
  category: Programming Languages
  category_slug: programming-languages
  tags: ruby,rails,blocks,procs,lambdas,metaprogramming,gems,idioms
  view_count: 0
  created_at: 1778695229
  updated_at: 1778695229
  entry_count: 8
  fields:
    - section: concepts
      field: name
      type: string
      example: Blocks
    - section: concepts
      field: type
      type: string
      example: Anonymous code chunks
    - section: concepts
      field: syntax
      type: string
      example: "{ |args| code } or do...end"
    - section: concepts
      field: description
      type: string
      example: Chunks of code passed to methods, fundamental t…
    - section: concepts
      field: example
      type: string
      example: 5.times { puts 'Hello' }
data:
  concepts:
    - name: Blocks
      type: Anonymous code chunks
      syntax: "{ |args| code } or do...end"
      description: Chunks of code passed to methods, fundamental to Ruby iteration and DSLs
      example: 5.times { puts 'Hello' }
    - name: Procs
      type: Stored blocks
      syntax: Proc.new { |args| code }
      description: Blocks converted to objects, can be stored in variables and passed around
      example: my_proc = Proc.new { |x| x * 2 }; my_proc.call(5)
    - name: Lambdas
      type: Strict procs
      syntax: "->(args) { code } or lambda { |args| code }"
      description: Like procs but with strict arity checking and return semantics (like methods)
      example: my_lambda = ->(x) { x + 1 }; my_lambda.call(3)
    - name: Metaprogramming
      type: Runtime code generation
      syntax: define_method, method_missing, send, class_eval
      description: "Writing code that writes code: dynamic method definition, method interception, eval families"
      example: "define_method(:greet) { |name| puts \"Hello, #{name}\" }"
    - name: Mixins (Modules)
      type: Shared behavior
      syntax: module MyModule; def method; end; end; class Foo; include MyModule; end
      description: Share methods across classes without inheritance, avoid multiple inheritance
      example: module Comparable; def <(other); self <=> other == -1; end; end
    - name: Enumerable
      type: Collection protocol
      syntax: include Enumerable; def each; end
      description: "Module providing iteration methods (map, select, reduce) to any class implementing #each"
      example: class MyCollection; include Enumerable; def each(&block); items.each(&block); end; end
    - name: Singleton Methods
      type: Per-object methods
      syntax: "def obj.method; end or obj.define_singleton_method(:m) { }"
      description: Methods defined on a single object instance, not its class
      example: "str = 'hello'; def str.shout; self.upcase + '!'; end; str.shout # => 'HELLO!'"
    - name: Method Missing
      type: Dynamic dispatch
      syntax: def method_missing(name, *args, &block); end
      description: Intercept calls to undefined methods for DSLs, proxies, and dynamic behavior
      example: "def method_missing(name); name.to_s.reverse; end; obj.hello #=> 'olleh'"