For [Code Block, Proc, Lambda, and Closure in Ruby]()

construction.rb

# Code Block
#1. {} Mostly used as a one-liner
{ puts 'Hi' }
#2. do end
do 
  puts 'Hi'
end
# example: arguments are wrapped between ||
[1, 2].map {|num| num * 2}

# Proc
#1. Proc.new followed by a code block
Proc.new { puts 'Hi' }
Proc.new do
  puts 'Hi'
end
#2. proc followed by a code block
proc { puts 'Hi' }
proc do
  puts 'Hi'
end
# example: arguments are wrapped between ||
times_2 = proc { |num| num * 2 }

# Lambda
# 1. lambda followed by a code block
lambda { puts 'Hi' }
lambda do
  puts 'Hi'
end
#2. -> (stabby lambda)
-> { puts 'Hi' }
-> do
  puts 'Hi'
end
#example: -> takes argument outside of {}
times_2 = -> (num) { num * 2 }

# Only -> takes argument outside of {}
->(arg) { puts arg }
# The rest takes argument in between ||
{ |arg| puts arg }
proc do |arg|
  puts arg
end
lambda { |arg| puts arg }