C# 设计模式-解释器模式

//抽象解释接口
public interface IExpression
{
    void Interpret(StringBuilder sb);
}
//单词解释（非终结符解释）
public class WordExpression : IExpression
{
    private string _value;

    public WordExpression(string value)
    {
        _value = value;
    }

    public void Interpret(StringBuilder sb)
    {
        sb.Append(ChineseEnglishDict.GetEnglish(_value.ToLower()));
    }
}
//标点符号解释（终结符解释）
public class SymbolExpression : IExpression
{
    private string _value;

    public SymbolExpression(string value)
    {
        _value = value;
    }

    public void Interpret(StringBuilder sb)
    {
        switch (_value)
        {
            case ".":
                sb.Append("。");
                break;
        }
    }
}
//容器（保存解释器中所对应的具体值）
public static class ChineseEnglishDict
{
    private static Dictionarystring, string> _dictory = new Dictionarystring, string>();

    static ChineseEnglishDict()
    {
        _dictory.Add("this", "这");
        _dictory.Add("is", "是");
        _dictory.Add("an", "一个");
        _dictory.Add("apple", "苹果");
    }

    public static string GetEnglish(string value)
    {
        return _dictory[value];
    }
}

//调用
public static void Main(string[] args)
{
    string englist = "This is an apple.";
    StringBuilder sb = new StringBuilder();
    List expressions = new List();
    string[] elements = englist.Split(new char[] { ‘.‘ }, StringSplitOptions.RemoveEmptyEntries);
    foreach (string element in elements)
    {
        string[] words = element.Split(new char[] { ‘ ‘ }, StringSplitOptions.RemoveEmptyEntries);
        foreach (string word in words)
        {
            expressions.Add(new WordExpression(word));
        }
        expressions.Add(new SymbolExpression("."));
    }
    foreach (IExpression expression in expressions)
    {
        expression.Interpret(sb);
    }
    Console.WriteLine(sb.ToString());
}