学步园

文法树抽象

using System;<br /> public abstract class Interpretor {<br /> private string _Expression;<br /> public Interpretor(string expression)<br /> {<br /> _Expression = expression;<br /> }</p> <p> public string Expression<br /> {<br /> get<br /> {<br /> return _Expression;<br /> }<br /> }</p> <p> public abstract string Transfer();<br /> }

文法树实例A

using System;</p> <p>public class FruitInterpretor : Interpretor<br /> {<br /> public FruitInterpretor(string expression):base(expression)<br /> { }</p> <p> public override string Transfer()<br /> {<br /> string result;<br /> switch (Expression)<br /> {<br /> case "fo":<br /> result = "橘子";<br /> break;<br /> case "fa":<br /> result = "苹果";<br /> break;<br /> case "fb":<br /> result = "香蕉";<br /> break;<br /> default:<br /> result = "未知的水果";<br /> break;</p> <p> }<br /> return result;<br /> }<br /> }

解释内容

using System;<br /> public class InterpreteContext {<br /> private string _InputContext;<br /> private string _OutputContext;<br /> public InterpreteContext(string context)<br /> {<br /> _InputContext = context;<br /> }</p> <p> public string InputContext<br /> {<br /> get<br /> {<br /> return _InputContext;<br /> }</p> <p> }</p> <p> public string OutputContext<br /> {<br /> get<br /> {<br /> return _OutputContext;<br /> }<br /> set {<br /> _OutputContext = value;<br /> }<br /> }</p> <p>}

调用代码

using System;<br /> using System.Collections.Specialized;<br /> using System.Collections.Generic;<br /> using System.Text;</p> <p>namespace InterpretePattern<br /> {<br /> class Program<br /> {<br /> static void Main(string[] args)<br /> {<br /> //使用堆栈来做<br /> int offset=0;<br /> Stack<string> words=new Stack<string>();<br /> InterpreteContext context = new InterpreteContext("i like fo fb and fa ");<br /> FruitInterpretor interpetor;<br /> for (int i = 0; i < context.InputContext.Length; i++)<br /> {<br /> switch (context.InputContext[i])<br /> {<br /> case ' ':<br /> words.Push(context.InputContext.Substring(offset,i-offset));<br /> offset=i+1;<br /> break;<br /> default:<br /> break;<br /> }<br /> }<br /> foreach (string express in words)<br /> {<br /> if (express.Length == 2 && express.StartsWith("f"))<br /> {<br /> interpetor = new FruitInterpretor(express);<br /> context.OutputContext = interpetor.Transfer() + " " + context.OutputContext;<br /> }<br /> else<br /> context.OutputContext = express + " " + context.OutputContext;<br /> }<br /> //string result = words.ToString();<br /> Console.WriteLine(context.OutputContext);<br /> Console.ReadKey();<br /> }<br /> }<br /> }<br />

执行结果：

i like 橘子 香蕉 and 苹果