[SO] Assign the object reference not the object

test.jl

type Chain
  value :: Int
  right :: Chain
  left :: Chain
  #Make the last link in the chain point to itself
  #so as to spare us from the julia workaround for nulls
  Chain(value::Int) = (chain = new(); chain.value = value; chain.right = chain; chain.left = chain; chain)
end


function rotateright(x::Chain)
  temp = x
  x = x.left
  temp.left = x.right
  x.right = temp
  x
end


c=Chain(0)

cr = Chain(10)
cl = Chain(20)
c.left = cl
c.right = cr

out = rotateright(c)

more complicated case:

crr = Chain(110)
crl = Chain(120)
clr = Chain(210)
cll = Chain(220)

cr.left = crl
cr.right = crr
cl.left = cll
cl.right = clr

out = rotateright(c)