C#编译器，很吸引人的哟

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; using System.Collections; namespace complier { public partial class Form1 : Form { OpenFileDialog file = new OpenFileDialog(); public Form1() { InitializeComponent(); txtOutput.SelectAll(); } private string[] token; //标识符表 private int tokenIndex = 0; //标识符表指针 private long[] constant; //整型常数表 private int constantIndex = 0; //整型常数表指针 private double[] dblConstant; //浮点常数表 private int dblConstantIndex = 0; //浮点常数表指针 private string[] strConst; //字符串表 private int strConstIndex; //字符串表指针 private char[] charConst; //字符表 private int charConstIndex = 0; //字符表指针 private string input; //存放待识别的源程序字符串 private int inputIndex = 0; //input字符串指针 private char ch; //存放最新读进的源程序字符 private string strToken; //存放构成单词符号的字符串 private bool scanned = false; //是否扫描过至少一次 private static string[] tokenReserve = { "If", "else", "while", "read", "write", "int", "real", }; //C#保留关键字表(7个) //将下一输入字符读到ch中，搜索指示器前移一字符位置 private void getChar() { ch = input[inputIndex]; inputIndex++; } //将ch中的字符连接到strToken之后 private void concat() { strToken += ch; } //判断ch中的字符是否为字母 private bool isLetter() { if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z')) return true; else return false; } //判断ch中的字符是否为数字 private bool isDigit() { if (ch >= '0' && ch <= '9') return true; else return false; } //对strToken中的字符串查找保留字表，若它是一个保留字则返回其编码，否则返回0 private int reserve() { int i; bool notFound = true; string s = strToken; for (i = 0; notFound && i < tokenReserve.Length; i++) { if (tokenReserve[i] == s) notFound = false; } if (notFound) return 0; else return i; } //将搜索指示器回调一个字符位置，将ch置为空白字符 private void retract() { inputIndex--; } //将strToken中的标识符插入符号表（表中不存在该元素时才插入），返回符号表指针 private int insertId() { //先在符号表里找该元素 int i; bool notFound = true; string s = strToken; for (i = 0; notFound && i < token.Length; i++) { if (token[i] == s) notFound = false; } //没找到 if (notFound) { token[tokenIndex] = strToken; tokenIndex++; return (tokenIndex - 1); } //找到了 else return i - 1; } //将strToken中的整型常数插入整型常数表（表中不存在该元素时才插入），返回整型常数表指针 private int insertConst() { int i; bool notFound = true; long s = int.Parse(strToken); for (i = 0; notFound && i < constant.Length; i++) { if (constant[i] == s) notFound = false; } //没找到 if (notFound) { constant[constantIndex] = int.Parse(strToken); constantIndex++; return (constantIndex - 1); } //找到了 else return i - 1; } //将strToken中的浮点型常数插入浮点常数表（表中不存在该元素时才插入），返回浮点常数表指针 private int insertDblConst() { int i; bool notFound = true; double s = double.Parse(strToken); for (i = 0; notFound && i < dblConstant.Length; i++) { if (dblConstant[i] == s) notFound = false; } //没找到 if (notFound) { dblConstant[dblConstantIndex] = double.Parse(strToken); dblConstantIndex++; return (dblConstantIndex - 1); } //找到了 else return i - 1; } //将strToken中的字符串插入字符串表（表中不存在该元素时才插入），返回字符串表指针 private int insertString() { int i; bool notFound = true; string s = strToken; for (i = 0; notFound && i < strConst.Length; i++) { if (strConst[i] == s) notFound = false; } //没找到 if (notFound) { strConst[strConstIndex] = strToken; strConstIndex++; return (strConstIndex - 1); } //找到了 else return i - 1; } //将strToken中的字符插入字符表（表中不存在该元素时才插入），返回字符表指针 private int insertChar() { int i; bool notFound = true; char c = ch; for (i = 0; notFound && i < charConst.Length; i++) { if (charConst[i] == c) notFound = false; } //没找到 if (notFound) { charConst[charConstIndex] = ch; charConstIndex++; return (charConstIndex - 1); } //找到了 else return i - 1; } //Scan方法 private string scan() { strToken = ""; int code, value; getChar(); //标识符及保留字 if (isLetter() || ch == '_') { if (input.Length > 1) { while ((isLetter() || isDigit() || (ch == '_')) && inputIndex < input.Length) { concat(); getChar(); } if (inputIndex < input.Length) retract(); else if (inputIndex == input.Length) { if (isLetter() || isDigit() || (ch == '_')) concat(); else retract(); } code = reserve(); if (code == 0) { value = insertId(); return (strToken + " < @ID" + ", " + value.ToString() + " >"); } else return (strToken + " < @RESERVED_WORD_" + code.ToString() + ", - >"); } else { return (ch + " < @ID" + ", 0 >"); } } //整型常数和浮点常数 else if (isDigit()) { if (input.Length > 1) { while (isDigit() && inputIndex < input.Length) {