A RingList is a list of distinct values that is unchanged by rotation. These can be created by giving a list of values or a one-dimensional array of values:

julia> a = RingList(1,2,3,4);

julia> b = RingList([2,3,4,1]);

julia> a==b
true

In this list, a stands for a RingList.

• length(a) gives the number of elements held in the RingList.
• keys(a) returns an iterator of the elements in a.
• haskey(a,x) checks if x is an element of the RingList.
• Vector(a) returns a one-dimensional array of the elements in a.
• Set(a) returns the elements of a (as an unordered collection).
• a[x] returns the next element after x in a.
• previous(a,x) returns the element y with a[y]==x.
• first(a) returns an element of a; call first(a,true) to attempt try to return the smallest value held in a. Fails if a is empty.
• insert!(a,x) inserts the element a into the RingList. No guarantee where it will end up.
• delete!(a,x) removes x from the collection linking together its predecessor and successor.
• insertafter!(a,x,y) inserts x into a after y. For example:

julia> a = RingList(1,2,3)
RingList{Int64}(1,2,3)

julia> insertafter!(a,99,2)

julia> a
RingList{Int64}(1,2,99,3)

• reverse(a) returns a new RingList with the elements reversed.

julia> a = RingList(1,2,3,4,5)
RingList{Int64}(1,2,3,4,5)

julia> b = reverse(a)
RingList{Int64}(1,5,4,3,2)