public UnaryExpression(AbstractExpression e) { this.e = e; }
public DisExpression(AbstractExpression e1, AbstractExpression e2) : base(e1, e2) { }
public BinaryExpression(AbstractExpression e1, AbstractExpression e2) { this.e1 = e1; this.e2 = e2; }
public ConjExpression(AbstractExpression e1, AbstractExpression e2) : base(e1, e2) { }
public NegExpression(AbstractExpression e) : base(e) { }