block.rb

p [*1..5].map { |i| i * 2 }
p ([*1..5].map { |i| i * 2 })

p [*1..5].map do |i| i * 2 end
p ([*1..5].map) do |i| i * 2 end
p ([*1..5].map do |i| i * 2 end)

def hello(x)
  puts "hi"
  if block_given?
    yield x
  end
  puts "hello"
end

hello("kk") { |name| puts name }