# File lib/ruote/dboard/mutation.rb, line 90
    def initialize(dboard, wfid, tree)

      @dboard = dboard
      @points = []
      @ps = @dboard.ps(wfid)

      walk(@ps.root_expression, Ruote.compact_tree(tree))

      @points = @points.sort_by { |point| point.fei.expid }
    end