pick states

>>

Creating a branch of states, as well as a new cursor:

comp-x (>> states branch-key) p1 p2

Notice that the structure of states is a tree of data and cursor:

{}
  :cursor $ [] :a
  :data $ {}

  :b $ {}
    :data $ {}
      :c $ {}
        :data $ {}

When (>> states :b) is evaluated, new piece of data is generated:

{}
  :cursor $ [] :a :b
  :c $ {}
    :data $ {}

In an older version, cursor and states are two separated variables, but now combined for convenience.