编译语言-语法分析器的设计

1、 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;impo

2、rt java.awt.*;import java.awt.event.*;import java.io.*;import java.util.LinkedList;public class AnalysisOfGrammer extends JAppletprivate 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

3、");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

4、 JPanel();private JTextArea jta1 = new JTextArea();private String grammer = new String50;private int count = 0;private LinkedList<ViablePrefixe> list = new LinkedList<ViablePrefixe>();private Object content = new Object1004;int num1 = 0;String cache = new String50100;int location = new i

5、nt50;int back = 0;public void clear1()grammer = null;public void 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(

6、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.a

7、ddActionListener(new ActionListener()public void actionPerformed(ActionEvent e)jta1.setText("");open(););jbt2.addActionListener(new ActionListener()public void actionPerformed(ActionEvent e)if(jta1.getText().equals("")JOptionPane.showMessageDialog(null, "请打开文法文件！");else

8、DNF();list.get(1).setNextState("接受态");for(int k = 0 ; k < list.size() ; k+)contentk0 = list.get(k).getState();contentk1 = list.get(k).getProjectSet();contentk2 = list.get(k).getNextSign();contentk3 = list.get(k).getNextState();String columnName = "状态","项目集","后继符

9、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(););public int getleng(String s)/获得一个字符串数组的真实长度int len = 0;while(slen!=null)len+;return len;public void DNF()

10、/自动机的构成int c = 0;int flag = new int100;String start = "S'-.>"+grammer0.substring(0, 1);flagnum1 = createI(start);/初态集建立locationnum1 = getleng(cachenum1);while(back <= num1)if(c < locationback && flagback = 0)num1+;list.get(back).setNextState(list.get(back).getNextState

11、()+"S"+num1+" ");flagnum1 = createI(cachebackc);locationnum1 = getleng(cachenum1);c+;elseback+;c = 0;public int 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="

12、;"boolean gra = new booleancount;int c = 1;int loop = 0;for(int k = 0 ; cachek0 != null; k+)if(cachek0.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 =

13、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;else if(old.equals("归约")num1-;rene

14、w = old.substring(0,k-1)+"S"+loop+old.substring(k+staleng+1, old.length()+" "list.get(back).setNextState(renew);break;return end;cachenum10 = s;String set = cachenum10 + " "if(num1 < list.size()nextsign=list.get(num1).getNextSign();nextstate=list.get(num1).getNextSta

15、te();set = list.get(num1).getProjectSet()+cachenum10 + " "if(findNext(s).equals("#")set = s;nextsign = "#"nextstate = "归约"ViablePrefixe o = new ViablePrefixe(state,set,nextsign,nextstate);list.add(o);return 1;elsewhile(true)int i = 0;for(; i < count; i+)if(

16、grammeri.substring(0, 1).equals(head)&&grai!=true)set = set + addPoint(grammeri) +" "cachenum1c+ = addPoint(grammeri);if(findNext(addPoint(grammeri).matches("A-Z")&&grai!=true)grai = true;head = findNext(addPoint(grammeri);break;/for循环结束if(i >= count &&

17、 head.equals(findNext(s).substring(0,1) break;else if(i >= count)head = grammer0.substring(0,1);/while循环结束int cc = 0; /设置下一状态的值String nextS = new String50;for(int i = 0 ; cachenum1i!=null; i+)int j = 0;boolean f = false;for(; nextSj!=null;j+)if(findNext(cachenum1i).equals(nextSj)f = true; break;/

18、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)nextScc+ = findNext(cachenum1j);nextsign = nextsign+findNext(cachenum1j)+" "/for i 循环结束ViablePrefixe o = new ViablePrefixe(state,set,nextsign,nextstate);list.add(o);return end;public int show(String s, String grammer)/文法的拆分

19、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)grammercount+ = str + s.substring(flag1, i);elsegrammercount+ = s.substring(fl

20、ag1, i);flag1 = i + 1;lastSign = true;else if(s.substring(i, i+1).equals("n")if(lastSign)grammercount+ = str + s.substring(flag1, i);elsegrammercount+ = s.substring(flag1, i);flag1 = i+1;if(flag1+3 < s.length()str = s.substring(flag1, flag1+3);lastSign = false;else if(s.substring(i, i+1

21、).equals("r")if(lastSign)grammercount+ = str + s.substring(flag1, i);elsegrammercount+ = s.substring(flag1, i);i+;flag1 = i+1;if(flag1+3 < s.length()str = s.substring(flag1, flag1+3);lastSign = false;return count;private void open()/打开文件String s =""if(jfc.showOpenDialog(this)

22、= JFileChooser.APPROVE_OPTION)s = open(jfc.getSelectedFile();count = show(s,grammer);for(int i = 0 ; grammeri!=null ; i+)jta1.append(grammeri);jta1.append("n");private String open(File file)/打开文件String content1 = ""tryBufferedInputStream in = new BufferedInputStream(new FileInput

23、Stream(file);byte b = new bytein.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;private static String addPoint(String m)/在文法中添加.String t=""int i;for(i = 0 ; i <

24、; 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;private static String findNex

25、t(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;public class 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 nextState)this.state = state;jectSet = projectSet;this.nextSign = nextSign;this.n