simplify.java

symbman（大学作业）

public class Simplify extends Expression {
	
	private Expression e;
	
	public Simplify(Expression e) {
		this.e = (Expression)e.clone();
	}
	
	public Expression getExpression() { return e; }

	public Object clone() {
		return new Simplify(e);
	}

	public Expression derive(Symbol s) {
		return (e.eval()).derive(s);
	}
	
	public boolean equals(Expression ex) {
		if(!(ex instanceof Simplify)) return false;
		Simplify s = (Simplify)ex;
		return (s.getExpression()).equals(e);
	}

	public Expression eval() {
		return (e.eval()).simplify();
	}

	public Expression simplify() {
		return new Simplify((e.eval()).simplify());
	}

	public String toString() {
		StringBuffer res = new StringBuffer("(S(");
		res.append(e);
		res.append("))");
		return res.toString();
	}

}