Testing for undefined variables in ruby.

How to Check if a Value Exists in a Set of Nested Hashes in Ruby

Operators In Ruby: 6 Things (2 Min) You Need To Know

Python Tutorial 21 - How to test if a Variable has a Value (is None)

Ruby For Beginners #3 - If / Else Statements

How to Check if Variable is Undefined or Null in Javascript

Ruby Tutorial 2 - Variables

Ruby: Variable Assignment and Objects - 002

Pony Language - First Impression [Programming Languages Episode 34]

define_method - Metaprogramming in Ruby

02 - Test if a Variable or Function is Defined - Quality Assurance with Chai - freeCodeCamp Tutorial

"Gradual typing of Ruby at Scale" by Dmytro Petrashko and Paul Tarjan

Data Types & Variables in Ruby

RailsConf 2023 - Who Wants to be a Ruby Engineer? by Drew Bragg

Ruby Tutorials: attr_reader to read instance variables

RailsConf 2020 CE - Static Type Checking in Rails with Sorbet by Hung Harry Doan

[JA] Speeding up Instance Variables with Red-Black Trees / Aaron Patterson @tenderlove

How to Set Up VS Code for Ruby

RubyConf 2022: Don't @ me! Faster Instance Variables with Object Shapes by Aaron Patterson

The Ruby Dungeon: E05 - DRY, Variables, Proc Calls, Modules, Vars & Settings