Ruby¶

Dynamic, object-oriented language focused on simplicity and productivity

Overview¶

Ruby is an elegant, dynamic programming language with a focus on simplicity and productivity. Known for its readable syntax and powerful metaprogramming capabilities, Ruby is widely used for web development (Ruby on Rails), scripting, and automation.

With run, you can execute Ruby code instantly using the Ruby interpreter. The Ruby engine provides a stateful REPL where variables, methods, and classes persist across commands.

Language Aliases¶

run ruby "puts 'Hello'"
run rb "puts 'Hello'"
run irb "puts 'Hello'"
# Output: Hello (x3)

Basic Usage¶

Simple Output¶

run ruby "puts 'Hello, World!'"
# Output: Hello, World!

Variables and Interpolation¶

run ruby "name = 'Alice'; puts \"Hello, #{name}!\""
# Output: Hello, Alice!

Arrays and Iteration¶

run ruby "[1, 2, 3, 4, 5].each { |n| puts n * 2 }"
# Output:
# 2
# 4
# 6
# 8
# 10

Multi-line Code¶

# RECOMMENDED: Heredoc
run ruby << 'EOF'
users = [
  { name: 'Alice', age: 30 },
  { name: 'Bob', age: 25 }
]
users.each do |user|
  puts "#{user[:name]}: #{user[:age]}"
end
EOF

# OK: Single-line with semicolons
run ruby "arr = [1,2,3]; arr.each { |n| puts n * 2 }"

REPL Behavior¶

Ruby's REPL is STATEFUL - variables and methods persist across commands.