编译语言-语法分析器的设计

实验三语法分析器的设计一、实验内容设计、编写和调试构造LR（0）项目集规范簇或实现基于LR分析表对给定的符号串进行LR 分析的程序。

以下两个内容任选其中一项：（1）对于给定的文法，实现构造识别该文法全部活前缀DFA的程序。

（2）对于给定的LR分析表和符号串，设计程序以实现所输入符号串是否为合法符号串。

要求用JAVA语言编程。

（可参考实验指导书P149至P156）二、程序代码AnalysisOfGrammer.javapackage analysis;import javax.swing.*;import javax.swing.table.DefaultTableModel;import java.awt.*;import java.awt.event.*;import java.io.*;import java.util.LinkedList;publicclass AnalysisOfGrammer extends JApplet{private JFileChooser jfc = new JFileChooser(new File("."));private JButton jbt1 = new JButton("打开文法文件");private JButton jbt2 = new JButton("构造LR规范簇");private JButton jbt3 = new JButton("构造LR分析表");private JButton jbt4 = new JButton("清空");private JButton jbt5 = new JButton("退出");private JLabel jl1 = new JLabel("LR(0)项目集规范簇");private JLabel jl2 = new JLabel("LR(0)分析表");private JPanel p3 = new JPanel();private JTextArea jta1 = new JTextArea();private String[] grammer = new String[50];privateint count = 0;private LinkedList<ViablePrefixe>list = new LinkedList<ViablePrefixe>();private Object content[][] = new Object[100][4];int num1 = 0;String[][] cache = new String[50][100];int[] location = newint[50];int back = 0;publicvoid clear1(){grammer = null;}publicvoid clear2(){num1 = 0;list = null;content = null;cache = null;location = null;back = 0;}public AnalysisOfGrammer(){JPanel p1 = new JPanel();p1.setLayout(new GridLayout(1,5));p1.add(jbt1);p1.add(jbt2);p1.add(jbt3);p1.add(jbt4);p1.add(jbt5);add(p1,BorderLayout.NORTH);JPanel p4 = new JPanel();p4.setLayout(new GridLayout(1,2));JPanel p2 = new JPanel();p2.setLayout(new BorderLayout());p2.add(new JLabel("文法为："),BorderLayout.NORTH);p2.add(new JScrollPane(jta1),BorderLayout.CENTER);p4.add(p2);p4.add(p3);add(p4,BorderLayout.CENTER);jbt1.addActionListener(new ActionListener(){publicvoid actionPerformed(ActionEvent e){jta1.setText("");open();}});jbt2.addActionListener(new ActionListener(){publicvoid actionPerformed(ActionEvent e){if(jta1.getText().equals(""))JOptionPane.showMessageDialog(null, "请打开文法文件！");else{DNF();list.get(1).setNextState("接受态");for(int k = 0 ; k<list.size() ; k++){content[k][0] = list.get(k).getState();content[k][1] = list.get(k).getProjectSet();content[k][2] = list.get(k).getNextSign();content[k][3] = list.get(k).getNextState();}String columnName[] = {"状态","项目集","后继符号","后继状态"};JTable table = new JTable(content,columnName);p3.setLayout(new BorderLayout());p3.add(jl1,BorderLayout.NORTH);p3.add(new JScrollPane(table),BorderLayout.CENTER);}clear2();}});}publicint getleng(String[] s){//获得一个字符串数组的真实长度int len = 0;while(s[len]!=null){len++;}return len;}publicvoid DNF(){//自动机的构成int c = 0;int[] flag = newint[100];String start = "S'-.>"+grammer[0].substring(0, 1);flag[num1] = createI(start);//初态集建立location[num1] = getleng(cache[num1]);while(back<= num1){if(c<location[back] &&flag[back] == 0){num1++;list.get(back).setNextState(list.get(back).getNextState()+"S"+num1+" ");flag[num1] = createI(cache[back][c]);location[num1] = getleng(cache[num1]);c++;}else{back++;c = 0;}}}publicint createI(String t){//生成状态集int end = 0;String s = addPoint(t);String head = findNext(s);String state = "S"+num1;;String nextsign="";String nextstate="";boolean[] gra = newboolean[count];int c = 1;int loop = 0;for(int k = 0 ; cache[k][0] != null; k++){if(cache[k][0].equals(s)){loop = k;end = 2;break;}}if(end == 2){//更改后继状态String old = list.get(back).getNextState();String sta = "S"+num1;String renew = "";int staleng = sta.length();for(int k = 0 ; k<old.length()-staleng+1; k++ ){if(old.substring(k,k+staleng).matches(sta)||old.equals("归约")){num1--;renew =old.substring(0,k-1)+"S"+loop+old.substring(k+staleng+1, old.length())+" ";list.get(back).setNextState(renew);break;}elseif(old.equals("归约")){num1--;renew =old.substring(0,k-1)+"S"+loop+old.substring(k+staleng+1, old.length())+" ";list.get(back).setNextState(renew);break;}}return end;}cache[num1][0] = s;String set = cache[num1][0] + " ";if(num1<list.size()){nextsign=list.get(num1).getNextSign();nextstate=list.get(num1).getNextState();set = list.get(num1).getProjectSet()+cache[num1][0] + " ";}if(findNext(s).equals("#")){set = s;nextsign = "#";nextstate = "归约";ViablePrefixe o = new ViablePrefixe(state,set,nextsign,nextstate);list.add(o);return 1;}else{while(true){int i = 0;for(; i<count; i++){if(grammer[i].substring(0,1).equals(head)&&gra[i]!=true){set = set + addPoint(grammer[i]) +" ";cache[num1][c++] = addPoint(grammer[i]);if(findNext(addPoint(grammer[i])).matches("[A-Z]")&&gra[i]!=true){gra[i] = true;head = findNext(addPoint(grammer[i]));break;}}}//for循环结束if(i>= count&&head.equals(findNext(s).substring(0,1))) break;elseif(i>= count){head = grammer[0].substring(0,1);}}//while循环结束int cc = 0; //设置下一状态的值String[] nextS = new String[50];for(int i = 0 ; cache[num1][i]!=null; i++){int j = 0;boolean f = false;for(; nextS[j]!=null;j++){if(findNext(cache[num1][i]).equals(nextS[j])){f = true; break;}}//for j 的循环结束,查找有无相同的后继符号，f作为标记，相同的符号跳过，不同的记录下来,放在nestS[]里if(f != true){nextS[cc++] = findNext(cache[num1][j]);nextsign = nextsign+findNext(cache[num1][j])+" ";}}//for i循环结束ViablePrefixe o = new ViablePrefixe(state,set,nextsign,nextstate);list.add(o);}return end;}publicint show(String s, String[] grammer){//文法的拆分函数，显示在界面上，返回值是文法的条数boolean lastSign = false;//上一符号为\nint flag1 = 0;//上一符号位置int count = 0;String str = s.substring(flag1, flag1+3);for(int i = 0 ; i<s.length() ; i++){if(s.substring(i, i+1).equals("|")){if(lastSign)grammer[count++] = str + s.substring(flag1, i);elsegrammer[count++] = s.substring(flag1, i);flag1 = i + 1;lastSign = true;}elseif(s.substring(i, i+1).equals("\n")){if(lastSign)grammer[count++] = str + s.substring(flag1, i);elsegrammer[count++] = s.substring(flag1, i);flag1 = i+1;if(flag1+3 <s.length())str = s.substring(flag1, flag1+3);lastSign = false;}elseif(s.substring(i, i+1).equals("\r")){if(lastSign)grammer[count++] = str + s.substring(flag1, i);elsegrammer[count++] = s.substring(flag1, i);i++;flag1 = i+1;if(flag1+3 <s.length())str = s.substring(flag1, flag1+3);lastSign = false;}}return count;}privatevoid open(){//打开文件String s ="";if(jfc.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) s = open(jfc.getSelectedFile());count = show(s,grammer);for(int i = 0 ; grammer[i]!=null ; i++){jta1.append(grammer[i]);jta1.append("\n");}}private String open(File file){//打开文件String content1 = "";try{BufferedInputStream in =new BufferedInputStream(new FileInputStream(file));byte[] b = newbyte[in.available()];in.read(b,0,b.length);content1 = new String(b,0,b.length);in.close();}catch(IOException ex){jta1.setText("Error opening " + file.getName());}return content1;}privatestatic String addPoint(String m){//在文法中添加.String t="";int i;for(i = 0 ; i<m.length() ; i++){if(m.substring(i,i+1).equals(".")){if(i == m.length()-1)return m;t =m.substring(0,i)+m.substring(i+1,i+2)+"."+m.substring(i+2,m.length());break;}}if(i>m.length()-1)t = m.substring(0,3)+"."+m.substring(3,m.length());return t;}privatestatic String findNext(String m){//返回.后的字母String c = "#";for(int i = 0 ; i<m.length()-1 ; i++){if(m.substring(i,i+1).equals(".")){c= m.substring(i+1,i+2);}}return c;}}ViablePrefixe.javapackage analysis;publicclass ViablePrefixe {//活前缀类private String state = "";//状态private String projectSet = "";//项目private String nextSign = "";//后继符号private String nextState = "";//后继状态public ViablePrefixe(String state,String projectSet,String nextSign,String n extState){this.state = state;this.projectSet = projectSet;this.nextSign = nextSign;this.nextState = nextState;}public ViablePrefixe(String state,String projectSet,String nextSign){ this.state = state;this.projectSet = projectSet;this.nextSign = nextSign;}public ViablePrefixe(String state,String projectSet){this.state = state;this.projectSet = projectSet;}public ViablePrefixe(){}public StringgetState() {return state;}publicvoid setState(String state) {this.state = state;}public StringgetProjectSet() {return projectSet;}publicvoid setProjectSet(String projectSet) {this.projectSet = projectSet;}public StringgetNextSign() {return nextSign;}publicvoid setNextSign(String nextSign) {this.nextSign = nextSign;}public StringgetNextState() {return nextState;}publicvoid setNextState(String nextState) {this.nextState = nextState;}public StringtoString(){return state+" "+projectSet+" "+nextSign+" "+nextState+"\n"; }}三、实验结果。