package G4ip;+
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+
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import pizza.util.Hashtable;+
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import java.awt.*;+
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import G4ip.Form.*;+
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+
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+
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/** A label with a surrounding box.+
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  */+
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class MyLabel extends Label {+
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  public MyLabel() { super(); }+
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  public MyLabel(String s) { super(s); }+
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+
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  public void paint(Graphics g) {+
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    Dimension d = this.size();+
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    g.setColor(Color.gray);+
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    g.drawRect(0,0,d.width-1,d.height-1);+
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  }+
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}+
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+
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+
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/** Draws a frame on the screen containing a proof.+
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  */+
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public class ProofDisplay extends Frame {+
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  Button ok;+
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  Hashtable<int,Sequent> proof;      // contains the indexed sequents +
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+
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  /** The proof is represented in the hashtable.+
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    * @param proof is a hashtable; the structure of the proof (or tree) +
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    * is mapped onto a sequence of integers; each integer is a key for+
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    * a sequent stored in the hashtable.+
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    */+
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  public ProofDisplay(Hashtable<int,Sequent> iproof) {+
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    super("Proof");+
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    ok = new Button("Close");+
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    proof = iproof;+
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+
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    setLayout(new BorderLayout());+
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    // SOUTH+
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    Panel p = new Panel();+
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    p.add(ok);+
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    add("South",p);+
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+
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    //CENTER+
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    Panel display = new Panel();+
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    printproof(display,1);+
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    add("Center", display);+
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+
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    pack();+
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    show();+
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  }+
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+
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  /** Recovers the structure of the proofs from the hashtable representation.+
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    */+
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  public void printproof(Panel p,int index) {+
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    MyLabel l = new MyLabel(proof.get(index).toString());+
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    l.setAlignment(MyLabel.CENTER);+
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    p.setLayout(new BorderLayout());+
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    p.add("South",l); +
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    // axiom (do nothing)+
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    if ((proof.get(2*index) == null) && (proof.get(2*index+1) == null)) { +
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      return;    +
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    }+
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    // rule with a single premise+
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    if ((proof.get(2*index) != null) && (proof.get(2*index+1) == null)) { +
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      Panel np = new Panel();+
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      printproof(np,2*index);+
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      p.add("Center",np);+
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      return;  +
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    }+
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    // rule with two premises+
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    if ((proof.get(2*index) != null) && (proof.get(2*index+1) != null)) { +
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      Panel np1 = new Panel();+
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      Panel np2 = new Panel();+
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      printproof(np1,2*index);+
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      printproof(np2,2*index+1);+
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      p.add("West",np1);+
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      p.add("East",np2);+
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      return;+
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    }+
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    +
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  }+
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+
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  /** If either the "Close" or the "Window-destroy" button+
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    * is pressed, then close the window.+
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    */+
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  public boolean handleEvent(Event e)  {+
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    if (e.id == Event.ACTION_EVENT && e.target == ok) {+
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      this.finalize(); +
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      return true;+
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    }+
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    if (e.id == Event.WINDOW_DESTROY) {+
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      this.finalize(); +
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      return true;+
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    }+
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    return false;+
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  }+
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+
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  /** Closes the window.+
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    */+
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  public void finalize()+
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    { this.dispose();  }+
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  +
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}+
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