夫妻网站开发,网络媒体设计与制作,ozon电商平台如何入驻,聊天app开发需要多少钱递归下降语法制导翻译
实现含多条简单赋值语句的简化语言的语义分析和中间代码生成。
测试样例
begin
a:2; b:4;
c:c-1;
area:3.14*a*a;
s:2*3.1416*r*(hr);
end
#词法分析
public class analyzer {public static ListString llistnew ArrayList();static …递归下降语法制导翻译
实现含多条简单赋值语句的简化语言的语义分析和中间代码生成。
测试样例
begin
a:2; b:4;
c:c-1;
area:3.14*a*a;
s:2*3.1416*r*(hr);
end
# 词法分析
public class analyzer {public static ListString llistnew ArrayList();static MapInteger,Integer mapnew HashMap();final static String ID \\p{Alpha}(\\p{Alpha}|\\d)*;static int countLine1;/** 整形常数 NUM 正则表达式*/final static String NUM \\d\\d*;/** token 词法单元* 词符号 种别码 *//** 关键字 token*/static MapString, Integer TOKEN_KEYWORDS;/** 运算符/界符 token */static MapString, Integer TOKEN_OPERATOR_BOUNDARY;/** 其他单词 token*/static MapString, Integer TOKEN_ID_SUM;/** 文件根目录*/static final String ROOT_DIRECTORY program.txt;/*** 初始化 token 单元*/public static void initToken(){//种别码创建TOKEN_KEYWORDS new HashMapString, Integer(){//关键字{put(begin, 1);put(if, 2);put(then, 3);put(while, 4);put(do, 5);put(end, 6);}};TOKEN_OPERATOR_BOUNDARY new HashMapString, Integer(){//运算符和界符{put(, 13);put(-, 14);put(*, 15);put(/, 16);put(:, 17);put(:, 18);put(, 20);put(, 21);put(, 22);put(, 23);put(, 24);put(, 25);put(;, 26);put((, 27);put(), 28);put(#, 0);}};TOKEN_ID_SUM new HashMapString, Integer(){//标识符和整型常数{put(ID, 10);put(NUM, 11);}};}/*** 读 源程序 文件*/public static void ReadFile1() {FileInputStream fis null;InputStreamReader isr null;BufferedReader br null;try {fis new FileInputStream(ROOT_DIRECTORY);isr new InputStreamReader(fis, UTF-8); // 转化类br new BufferedReader(isr); // 装饰类String line;/** 记录 程序 行数 */while ((line br.readLine()) ! null) { // 每次读取一行分析一行boolean answer lexicalAnalysis(line);if(answer false){System.out.printf(ERROR 编译错误 第 %d 行出现 词法错误 \n, countLine);break;}countLine;}System.out.printf(词法分析完成\n);} catch (Exception ex) {ex.printStackTrace();} finally {try {br.close(); // 关闭最后一个类会将所有的底层流都关闭} catch (Exception ex) {ex.printStackTrace();}}}/** 判断key是否是其他单词*/private static boolean isIDOrSUM(String key){if (key.matches(ID) ) {llist.add(key);map.put(llist.size()-1,countLine);System.out.printf((%d, %s)\n, TOKEN_ID_SUM.get(ID), key);}else if (key.matches(NUM)) {llist.add(key);map.put(llist.size()-1,countLine);System.out.printf((%d, %s)\n, TOKEN_ID_SUM.get(NUM), key);}else {return false;}return true;}/*** 进行 词法分析* param word 要分析的字符串* return 结果*/public static boolean lexicalAnalysis(String word){word word.trim(); // 去首尾空格String[] strings word.split(\\p{Space}); // 分割字符串保证处理的字符串没有空格for (String string : strings) {/** 3种情况* 1. 关键字 end 关键字的后面一定是空格 * 2. 运算符/ 分界符 continue* 3. 其他单词 continue*/String key ;for (int i 0; i string.length(); i){String indexChar String.valueOf(string.charAt(i)) ;if(i1string.length()){if((indexCharstring.charAt(i1)).equals(//))return true;}/** 是 运算符 或者 关键字*/if (TOKEN_OPERATOR_BOUNDARY.containsKey(indexChar) ||TOKEN_KEYWORDS.containsKey(string.substring(i, string.length()))){if (key.length() 0) {if (isIDOrSUM(key) false) {/** 词法错误 */return false;}key ;}if(TOKEN_OPERATOR_BOUNDARY.containsKey(indexChar)) {/** 1. 是 运算符/分界符 */key indexChar;if(i 1 string.length() TOKEN_OPERATOR_BOUNDARY.containsKey(indexChar string.charAt(i1))){ // 运算分界符key string.charAt(i);}llist.add(key);map.put(llist.size()-1,countLine);System.out.printf((%d, %s)\n,TOKEN_OPERATOR_BOUNDARY.get(key),key);key ;}else if(TOKEN_KEYWORDS.containsKey(key string.substring(i, string.length()))) {/** 2. 是关键字*/llist.add(key);map.put(llist.size()-1,countLine);System.out.printf((%d, %s)\n,TOKEN_KEYWORDS.get(key),key);key ;break;}}else {/** 是其他单词*/key indexChar;/** 其他单词后面是 1. 换行2. 运算符/界符 3. 其他单词*/if(i1 string.length()){if (isIDOrSUM(key) false) {/** 词法错误 */return false;}}}}}return true;}public analyzer() {}public static void main(String[] args) {initToken();System.out.println(词法分析程序);System.out.println(从文件中读取程序);System.out.println();ReadFile1(); for(String s:llist) System.out.println(s);System.out.println();}}
语法分析
public class GrammarAnalysis {static char[] s new char[100];static int sing;static int i; //用来记录数组s中的下标static int error0;static void P() {if(Objects.equals(analyzer.llist.get(i), begin)) {i;S();
//处理if(Objects.equals(analyzer.llist.get(i), end)) {i;}else{System.out.println(error!--------不是结尾符号end程序第analyzer.map.get(i)行出现语法错误);error;i;}}else {System.out.println(error!--------缺少开头符号begin程序第analyzer.map.get(i)行出现语法错误);error;S();
//处理if(Objects.equals(analyzer.llist.get(i), end)) {i;}else{System.out.println(error!--------不是结尾符号end程序第analyzer.map.get(i)行出现语法错误);error;i;}}}static void S() {A();if(Objects.equals(analyzer.llist.get(i), ;)) {i;// if(s[i]!e) {S1();// }}else {System.out.println(error!-----------缺少结尾符号;程序第analyzer.map.get(i)行出现语法错误);error;i;S1();}}static void S1() {if(!Objects.equals(analyzer.llist.get(i), end)) {// i;S();}}static void A() {if(i1analyzer.llist.size()Objects.equals(analyzer.llist.get(i1), :)) {String timesanalyzer.llist.get(i),data1;SemanticAnalysis.ji;SemanticAnalysis.j2;data1 SemanticAnalysis.expression();//表达式SemanticAnalysis.memset(times,data1,,);i;i;E();if(Objects.equals(analyzer.llist.get(i), )) || Objects.equals(analyzer.llist.get(i), ;)) {if(Objects.equals(analyzer.llist.get(i), ))) {i;}}else {System.out.println(error!--------不是结尾符号或者程序第analyzer.map.get(i)行出现语法错误);error;i;}}else {System.out.println(error!---------不是赋值语句程序第analyzer.map.get(i)行出现语法错误);error;i;i;E();if(Objects.equals(analyzer.llist.get(i), )) || Objects.equals(analyzer.llist.get(i), ;)) {if(Objects.equals(analyzer.llist.get(i), ))) {i;}}else {System.out.println(error!--------不是结尾符号或者程序第analyzer.map.get(i)行出现语法错误);error;i;}}}static void E() {T();if(Objects.equals(analyzer.llist.get(i), ) || Objects.equals(analyzer.llist.get(i), -) || Objects.equals(analyzer.llist.get(i), ;) || Objects.equals(analyzer.llist.get(i), ))) {E1();}else {System.out.println(error!-----------不是结尾符号或者-或者或者程序第analyzer.map.get(i)行出现语法错误); error;E1();}}static void T() {F();if(Objects.equals(analyzer.llist.get(i), ) || Objects.equals(analyzer.llist.get(i), -) || Objects.equals(analyzer.llist.get(i), ;) || Objects.equals(analyzer.llist.get(i), )) || Objects.equals(analyzer.llist.get(i), *) || Objects.equals(analyzer.llist.get(i), /)) {T1();}}static void F() {if(Objects.equals(analyzer.llist.get(i), ()) {i;E();}else {i;}}static void T1() {if(Objects.equals(analyzer.llist.get(i), *)) {i;F();T1();}else if(Objects.equals(analyzer.llist.get(i), /)){i;F();T1();}}static void E1() {if(Objects.equals(analyzer.llist.get(i), )) {i;T();E1();}else if(Objects.equals(analyzer.llist.get(i), -)){i;T();E1();}}public static void main(String[] args) {Scanner scnew Scanner(System.in);System.out.println(词法分析程序);System.out.println(从文件中读取程序);System.out.println();analyzer.initToken();analyzer.ReadFile1();System.out.println(语法分析中....,请稍候);i0;sing0;if(Objects.equals(analyzer.llist.get(0), #)) System.exit(-1);P();if(Objects.equals(analyzer.llist.get(i), #)) {}else {System.out.println(error!-------不是结尾符号#analyzer.llist.get(i)i);error;}System.out.println(词法分析完成);System.out.println(共检查出error个语法错误);System.out.println(\n中间代码生成结果);for(int i 0;i SemanticAnalysis.elements.size();i) {Element e SemanticAnalysis.elements.get(i);System.out.println(e.times e.data1 e.op e.data2);}}}
语义分析
public class SemanticAnalysis {static int j0,t1;static ListElement elements new ArrayListElement();static void memset(String times,String data1,String op,String data2) {Element e new Element(times,data1,op,data2);elements.add(e);}public static String expression() { // 表达式String times,data1,op,data2;data1 term();while(analyzer.llist.get(j).equals() || analyzer.llist.get(j).equals(-)) {// 当前单词为、if(analyzer.llist.get(j).equals()) // op ;else // -op -;j;data2 term();times t (t);memset(times,data1,op,data2);data1 times;}return data1;}private static String term() { // 项String times,data1,op,data2;data1 factor();while(analyzer.llist.get(j).equals(*) || analyzer.llist.get(j).equals(/) ) { // 当前单词为*、/if(analyzer.llist.get(j).equals(*)) // *op *;else // /op /;j;data2 factor();times t (t);memset(times,data1,op,data2);data1 times;}return data1;}private static String factor() { // 因子String data ;if(analyzer.map2.get(analyzer.llist.get(j)) 10) { // IDdata analyzer.llist.get(j);j;} else if(analyzer.map2.get(analyzer.llist.get(j)) 11) { // NUMdata analyzer.llist.get(j);j;}else if(analyzer.llist.get(j).equals(()) { // 左括号j;data expression();if(analyzer.llist.get(j).equals()))j;} else {System.out.println(Error,表达式错误);}return data;}}
public class Element {String times;String data1;String op;String data2;Element(String times,String data1,String op,String data2) {this.times times;this.data1 data1;this.op op;this.data2 data2;}
}
