Remove sequential duplicates recursively

destutter.rb

def destutter list
  if list.length < 2
    list
  else
    a = list.shift
    a == list[0] ?
      destutter(list) :
      destutter(list).unshift(a)
  end
end

## Example usage
p destutter([0,"x","x",{foo:"bar"},{foo:"bar"},1,1,2,2,3,3,4,4])