ruby builders

# current behavior
def my_string arg
  s = "string"
  ["stuff", "to", "add"].each do |item|
    s << " "
    s << item
  end
  
  s
end

# i want to write
def my_string arg > s
  = "my string"
  ["stuff", "to", "add"].each do |item|
    << " "
    << item
  end
  
end