public void addPair(String booleanAssign){
  if (!booleanAssign.startsWith("!")) {
    addPair(booleanAssign,ValueFactory.create(true));
  }
 else {
    addPair(booleanAssign.substring(1,booleanAssign.length()),ValueFactory.create(false));
  }
}

public void addPair ( String booleanAssign ) { if ( ! booleanAssign . startsWith ( "!" ) ) { addPair ( booleanAssign , ValueFactory . create ( true ) ) ; } else { addPair ( booleanAssign . substring ( 1 , booleanAssign . length ( ) ) , ValueFactory . create ( false ) ) ; } }
adds a new ( var , value ) pair as determined by the form of the argument . if the argument starts with an exclamation mark , the value is set to false , else the value is set to true .
