made == for LinkedLists iterative

src/list.jl

@@ -20,7 +20,20 @@ head(x::Cons) = x.head
 tail(x::Cons) = x.tail
 
 Base.:(==)(x::Nil, y::Nil) = true
-Base.:(==)(x::Cons, y::Cons) = (x.head == y.head) && (x.tail == y.tail)
+function Base.:(==)(x::LinkedList, y::LinkedList) 
+ # can be changed to the more elegant
+ # Base.:(==)(x::Cons, y::Cons) = (x.head == y.head) && (x.tail == y.tail)
+ # once julia supports tail call recursions
+ while x isa Cons && y isa Cons
+ x.head == y.head || return false
+ x = x.tail
+ y = y.tail
+ end
+ if x isa Cons || y isa Cons
+ return false
+ end
+ return true
+end
 
 function Base.show(io::IO, l::LinkedList{T}) where T
  if isa(l,Nil)