rule amalgam {
  pattern { X [form = "du", upos = "P+D"] }
  commands {
    add_node D :> X;    % Create a new node called `D` and place it just after `X`
    X.form = "de";      % Change the form of `X` to `de`
    X.upos = ADP;       % Set the `ADP` tag for the preposition "de"
    D.form = "le";      % Add the form feature of `D` to `le`
    D.upos = DET;       % Set the `DET` tag for the determiner "le"
  }
}