# File lib/parse_tree.rb, line 1191
  def process(input, verbose = nil, file = "(string)", line = -1)
    case input
    when Array then
      @unifier.process(input)
    when String then
      pt = self.parse_tree_for_string(input, file, line, verbose).first
      @unifier.process(pt)
    else
      raise ArgumentError, "Unknown input type #{input.inspect}"
    end
  end