广州大学编译原理实验报告.rar

package 实验1; import java.util.regex.Matcher; import java.util.regex.Pattern; import java.util.*; public class Lexical_analysis { Map<String, Integer> map;//符号及其对应种别编码 Lexical_analysis(){ map=new HashMap<String, Integer>(); } public void init() {//初始化Key和Value map.put("if",0); map.put("then",1); map.put("else",2); map.put("while", 3); map.put("begin", 4); map.put("do",5); map.put("end", 6); map.put("赋值语句",7); map.put(";",8); map.put("布尔表达式",9); map.put("#",10); map.put("语句",12); map.put("^",18); map.put("∨",19); map.put("+",34); map.put("*",36); map.put(":=",38); map.put("and",39); map.put("or",40); map.put("not",41); map.put("关系运算符",42); //六种关系运算符处理 map.put("<",42); map.put(">",42); map.put(">=",42); map.put("<=",42); map.put("=",42); map.put("<>",42); map.put("（",48); map.put("）",49); } public String replaceBlank(String str) {//去除空格,缩进等空白符号,初始测验使用方法 String dest = ""; if (str!=null) { Pattern p = Pattern.compile("\\s*|\t|\r|\n"); Matcher m = p.matcher(str); dest = m.replaceAll(""); } return dest; } //Character.isLetter(char); 判断字符是否为字母 //Character.isDigit(char); 判断字符是否为数字 public String recogize(String sentence) { StringBuffer buffer = new StringBuffer(); StringBuffer res=new StringBuffer(); System.out.print(sentence+'\t'); String arrays[]=sentence.split(" ");//以空格进行分割 for(int j=0;j<arrays.length;j++) { for(int i=0;i<arrays[j].length();i++) { char c=arrays[j].charAt(i); if(Character.isLetter(c)) {//如果开头是字母,那么该字符串可能是关键字或者变量 while((Character.isLetterOrDigit(c)||c=='_')) {//获取一整块字符,再进行是关键字还是变量的判断 buffer.append(c); i++; if(i<arrays[j].length()) c=arrays[j].charAt(i); else break; } i--;//回退一格 if(map.containsKey(buffer.toString())) {//判断是否为关键词 res.append("<"+map.get(buffer.toString())+","+buffer.toString()+">"); System.out.print("<"+map.get(buffer.toString())+","+buffer.toString()+">\t"); } else { res.append("<56,变量>"); System.out.print("<56,变量>"); } buffer.delete(0, buffer.length()); } else if(Character.isDigit(c)) {//如果开头是数字的话，只可能是数值 while(Character.isDigit(c)) {//获取完整数值 buffer.append(c); i++; if(i<arrays[j].length()) c=arrays[j].charAt(i); else break; } i--; String binary=Integer.toBinaryString(Integer.parseInt(buffer.toString()));//将数字转化为二进制字符 res.append("<57,"+binary+">"); System.out.print("<57,"+binary+">\t"); buffer.delete(0, buffer.length()); } else if(c==' '){ continue; } else {//如果开头是符号的话,只可能是标识符或者运算符等情况 while(!Character.isLetterOrDigit(c)) { buffer.append(c); i++; if(i<arrays[j].length()) c=arrays[j].charAt(i); else break; } i--; if(map.containsKey(buffer.toString())) { if(map.get(buffer.toString())==42) {//判断是否为关系运算符 res.append("<"+map.get(buffer.toString())+","+"关系运算符"+">"); System.out.print("<"+map.get(buffer.toString())+","+"关系运算符"+">\t"); } else { res.append("<"+map.get(buffer.toString())+","+buffer.toString()+">"); System.out.print("<"+map.get(buffer.toString())+","+buffer.toString()+">\t"); } } buffer.delete(0, buffer.length()); } } } System.out.print(res.toString()); return res.toString(); } }