java编写的LL文法.docx

/*/Author：龙魂 /copyright-mythinfuture/教程“龙书”-李建中翻译的那版*/import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;public class test_1 public static void main(String args) throws IOException InputStreamReader ir=null; BufferedReader in=null; String input=null; boolean exit =false; boolean flag=false; StringBuffer stack=new StringBuffer($E); StringBuffer inputString=null; StringBuffer outputString=new StringBuffer( ); int i=0; char _index=new char E,E,T,T,F ; char _list=new char T,E,+,T, ; System.out.println(|*|); System.out.println(| LL(1)简单模拟测试 |); System.out.println(|*|); System.out.println(| 友情提示: tt|); System.out.println(| 空字符用& 表示 id用i表示 t|); System.out.println(|*|); System.out.println(|文法如下所示: t|); System.out.println(| E-TE tt|); System.out.println(| E-+TE|& tt|); System.out.println(| T-FT tt|); System.out.println(| T-* FT|& tt|); System.out.println(| F-(E)|id tt|); System.out.println(|*|); while(!exit) System.out.print(请输入测试串:); stack=new StringBuffer($E); ir=new InputStreamReader(System.in); in=new BufferedReader(ir); input=in.readLine(); /* 检验输入是否错误 */ flag=test_1.checkCommand(input); if(flag=true) inputString=new StringBuffer(input); /初始化输入串 inputString.append($); /以 $作为终结符 System.out.println(-); System.out.println(-); System.out.println(|t 栈 t |t 输入 t|t 输出tt|); System.out.println(-); while(stack.length()=1) i=stack.length()-1; /堆栈下角标 String temp=| +stack.toString(); for(int j=0;j(15-stack.length();j+) temp+= ; temp+=| +inputString.toString(); for(int j=0;j(20-inputString.length();j+) temp+= ; temp+=| +outputString.toString(); if(outputString.equals( ) temp+=ttt|; else for(int j=0;jTE); else System.out.println(出错: E 无法与 +inputString.charAt(0)+ 进行比对规约); break; else if(stack.charAt(i)=F) if(inputString.charAt(0)=i) stack.deleteCharAt(i); stack.append(i); outputString=new StringBuffer(F-id); else if(inputString.charAt(0)=() stack.deleteCharAt(i); stack.append()E(); outputString=new StringBuffer( F-(E) ); else System.out.println(出错: E 无法与 +inputString.charAt(0)+ 进行比对规约); break; else if(stack.charAt(i)=T) if(inputString.charAt(0)=i)|(inputString.charAt(0)=() stack.deleteCharAt(i); stack.append(TF); outputString=new StringBuffer( T-FT ); else System.out.println(出错: E 无法与 +inputString.charAt(0)+ 进行比对规约); break; else if(stack.charAt(i)=) if(String.valueOf(stack.charAt(i-1)+).equals(T) if(inputString.charAt(0)=+)|(inputString.charAt(0)=)|(inputString.charAt(0)=$) stack.deleteCharAt(i); stack.deleteCharAt(i-1); outputString=new StringBuffer( T-& ); else if(inputString.charAt(0)=*) stack.deleteCharAt(i); stack.deleteCharAt(i-1); stack.append(TF*); outputString=new StringBuffer( T-*FT ); else System.out.println(出错: E 无法与 +inputString.charAt(0)+ 进行比对规约); break; else if(String.valueOf(stack.charAt(i-1)+).equals(E) if(inputString.charAt(0)=+) stack.deleteCharAt(i); stack.deleteCharAt(i-1); stack.append(ET+); outputString=new StringBuffer( E-+TE ); else if(inputString.charAt(0)=)|(inputString.charAt(0)=$) stack.deleteCharAt(i); stack.deleteCharAt(i-1); outputString=new StringBuffer(E-&); else System.out.println(出错: E 无法与 +inputString.charAt(0)+ 进行比对规约); break; else /当堆栈首部中出现小写字符时候 stack.deleteCharAt(i-); inputString.deleteCharAt(0); outputString=new StringBuffer( ); System.out.println(-); System.out.println(您是否继续进行测试操作? Yes or No?); System.out.print(请输入:); ir=new InputStreamReader(System.in); in=new BufferedReader(ir); input=in.readLine(); if(!input.trim().toUpperCase().equals(Y) exit=true; /* * 检查输入串是否符合标准 * */private static boolean checkCommand(String input) int i=0; / while(iinput.length() if(input.charAt(i)=i)|(input.charAt(i)=&)|(input.charAt(i)=+)|(input.charAt(i)=*)|(input.charAt(i)=()|(in