4J4ZN71 (hak) 30> ./run harold.rcl 
*** Total parsing time = 31 ms
*** There are no errors
*** Do you want to see the XML serialization? (y/n) [y] > y

<Or>
  <And>
    <Exists>
      <Var>Buyer</Var>
      <Atom>
        <Rel>purchase</Rel>
        <Var>Buyer</Var>
        <Var>Seller</Var>
        <Expr>
          <Fun>book</Fun>
          <Var>Author</Var>
          <Ind>LeRif</Ind>
        </Expr>
        <Data>49</Data>
      </Atom>
    </Exists>
    <Equal>
      <Var>Seller</Var>
      <Var>Author</Var>
    </Equal>
  </And>
  <And>
    <Exists>
      <Var>Buyer</Var>
      <And>
        <Atom>
          <Rel>purchase</Rel>
          <Var>Buyer</Var>
          <Var>Seller</Var>
          <Expr>
            <Fun>book</Fun>
            <Var>Author</Var>
            <Ind>LeRif</Ind>
          </Expr>
          <Var>Price</Var>
        </Atom>
        <Equal>
          <Var>Buyer</Var>
          <Var>Author</Var>
        </Equal>
      </And>
    </Exists>
    <Atom>
      <Rel>knows</Rel>
      <Var>Seller</Var>
      <Var>Author</Var>
    </Atom>
    <Atom>
      <Rel>high</Rel>
      <Var>Price</Var>
    </Atom>
  </And>
  <Or>
    <Atom>
      <Rel>purchase</Rel>
      <Ind>John</Ind>
      <Var>Seller</Var>
      <Expr>
        <Fun>book</Fun>
        <Var>Author</Var>
        <Ind>LeLisp</Ind>
      </Expr>
      <Var>Price</Var>
    </Atom>
    <And>
      <Exists>
        <Var>Buyer</Var>
        <Atom>
          <Rel>purchase</Rel>
          <Var>Buyer</Var>
          <Var>Seller</Var>
          <Expr>
            <Fun>book</Fun>
            <Var>Author</Var>
            <Ind>LeRif</Ind>
          </Expr>
          <Data>49</Data>
        </Atom>
      </Exists>
      <Equal>
        <Var>Seller</Var>
        <Var>Author</Var>
      </Equal>
    </And>
    <And>
      <Exists>
        <Var>Buyer</Var>
        <And>
          <Atom>
            <Rel>purchase</Rel>
            <Var>Buyer</Var>
            <Var>Seller</Var>
            <Expr>
              <Fun>book</Fun>
              <Var>Author</Var>
              <Ind>LeRif</Ind>
            </Expr>
            <Var>Price</Var>
          </Atom>
          <Equal>
            <Var>Buyer</Var>
            <Var>Author</Var>
          </Equal>
        </And>
      </Exists>
      <Atom>
        <Rel>knows</Rel>
        <Var>Seller</Var>
        <Var>Author</Var>
      </Atom>
      <Atom>
        <Rel>high</Rel>
        <Var>Price</Var>
      </Atom>
    </And>
  </Or>
  <Exists>
    <Var>Author</Var>
    <Or>
      <Atom>
        <Rel>purchase</Rel>
        <Ind>John</Ind>
        <Var>Seller</Var>
        <Expr>
          <Fun>book</Fun>
          <Var>Author</Var>
          <Ind>LeLisp</Ind>
        </Expr>
        <Var>Price</Var>
      </Atom>
      <And>
        <Exists>
          <Var>Buyer</Var>
          <Atom>
            <Rel>purchase</Rel>
            <Var>Buyer</Var>
            <Var>Seller</Var>
            <Expr>
              <Fun>book</Fun>
              <Var>Author</Var>
              <Ind>LeRif</Ind>
            </Expr>
            <Data>49</Data>
          </Atom>
        </Exists>
        <Equal>
          <Var>Seller</Var>
          <Var>Author</Var>
        </Equal>
      </And>
      <And>
        <Exists>
          <Var>Buyer</Var>
          <And>
            <Atom>
              <Rel>purchase</Rel>
              <Var>Buyer</Var>
              <Var>Seller</Var>
              <Expr>
                <Fun>book</Fun>
                <Var>Author</Var>
                <Ind>LeRif</Ind>
              </Expr>
              <Var>Price</Var>
            </Atom>
            <Equal>
              <Var>Buyer</Var>
              <Var>Author</Var>
            </Equal>
          </And>
        </Exists>
        <Atom>
          <Rel>knows</Rel>
          <Var>Seller</Var>
          <Var>Author</Var>
        </Atom>
        <Atom>
          <Rel>high</Rel>
          <Var>Price</Var>
        </Atom>
      </And>
    </Or>
  </Exists>
</Or>