部分代码见——词法分析器
expr221.txt
{
i1=14;
i2=i1+2*3;
i3=i1-5*(i2%2)+5;
if(i1==i4&&i2>=20){
i3=i3+1;}
else{
i3=i3+2;}
}
expr222.txt
{
m=12;n=21;
if(m<n){
t=m;m=n;n=t;
}
r=1;
d=m%n;
while(r!=0){m=n;n=r;r=m%n;}
}
Lab2Main.java
package sch.cauc.edu.token;
/**
*
*
* Lab2Main
* 创建人:xrzhang
* 时间：2018年5月16日-下午9:37:28
* @version 1.0.0
*
*/
public class Lab2Main {
/**
*
* 方法名：main
* 创建人：xrzhang
* 时间：2018年5月16日-下午9:37:34
* 邮件：[email protected]
* @param args void
* @exception
* @since 1.0.0
*/
public static void main(String[] args) {
//String srcFileName="test/expr221.txt";
String srcFileName="test/expr222.txt";
RecursionDescendParser parser = new RecursionDescendParser();
parser.doParse(srcFileName);
}
}
RecursionDescendParser.java
package sch.cauc.edu.token;
import java.beans.Expression;
import javax.management.timer.TimerMBean;
import javax.sound.midi.Sequence;
/**
*
* SimpleBlock语言的递归下降分析
* RecursionDescendParser
* 创建人:xrzhang
* 时间：2018年5月16日-上午10:14:16
* @version 1.0.0
*
*/
public class RecursionDescendParser {
private BlockLexer lexer=null;
private Token lookAhead = null;
public RecursionDescendParser(){
}
public void doParse(String filePath){
lexer = new BlockLexer(filePath);
this.parse();
}
public void matchToken(TokenType type,String functionName){
System.out.println("In matchToken();-----jmzhang-----"+lookAhead.getType());
if(lookAhead.getType()!=type){
parsingError(type.toString(),functionName);
}
lookAhead =lexer.nextToken();
}
public void parsingError(String types,String functionName){
System.out.println("Parsing Error! in"+functionName);
System.out.println("encounter "+lookAhead.getLexeme());
System.out.println("at line "+lookAhead.getLine()+",column "+lookAhead.getColumn());
System.out.println("while expecting "+types);
System.exit(1);
}
/**
*
* 调用开始符号对应的方法，进行语法分析
* 方法名：parse
* 创建人：xrzhang
* 时间：2018年5月16日-上午10:27:14
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
public void parse() {
System.out.println("In parse();-----jmzhang-----");
lookAhead=lexer.nextToken();
simpleblock();
System.out.println("Parsing Success!");
}
public void simpleblock() {
System.out.println("In simpleblock();-----jmzhang-----");
if(lookAhead.getType()==TokenType.LBRACKET){
matchToken(TokenType.LBRACKET, "simpleblock");
System.out.println("In simpleblock();-----jmzhang-----11");
Sequence();
System.out.println("In simpleblock();-----jmzhang-----12");
matchToken(TokenType.RBRACKET, "simpleblock");
System.out.println("In simpleblock();-----jmzhang-----13");
if(lookAhead.getType()==TokenType.LBRACKET){
simpleblock();
}
}else{
System.out.println("In simpleblock();-----jmzhang-----2");
parsingError(TokenType.LBRACKET.toString(), "simpleblock");
}
}
/**
*
* sequence=assognmentStatement sequence |
* ifStatement sequence |
* whileStatement sequence |
* epsilon
* S->AS | IS |WS | ε
* 方法名：Sequence
* 创建人：xrzhang
* 时间：2018年5月16日-下午8:54:23
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
private void Sequence() {
System.out.println("In Sequence();-----jmzhang-----");
if(lookAhead.getType()==TokenType.IDENTIFIER){
System.out.println("In Sequence();-----jmzhang-----1");
assignmentStatement();
Sequence();
}else if (lookAhead.getType()==TokenType.KEY_IF) {
System.out.println("In Sequence();-----jmzhang-----2");
ifStatement();
Sequence();
}else if (lookAhead.getType()==TokenType.KEY_WHILE) {
System.out.println("In Sequence();-----jmzhang-----WHILE");
whileStatement();
Sequence();
}else if (lookAhead.getType()==TokenType.RBRACKET) {
//match epslon
System.out.println("In Sequence();-----jmzhang-----3");
}else {
System.out.println("In Sequence();-----jmzhang-----4");
String errorTypes=TokenType.IDENTIFIER.toString()+","+TokenType.RBRACKET.toString();
parsingError(errorTypes, "sequence");
}
}
private void whileStatement() {
System.out.println("In whileStatement();-----jmzhang-----");
matchToken(TokenType.KEY_WHILE, "whileStatement");
matchToken(TokenType.LPAREN, "whileStatement");
Boolexpression();
matchToken(TokenType.RPAREN, "whileStatement");
matchToken(TokenType.LBRACKET, "whileStatement");
Sequence();
matchToken(TokenType.RBRACKET, "whileStatement");
}
private void Boolexpression() {
System.out.println("In Boolexpression();-----jmzhang-----");
if (lookAhead.getType()==TokenType.IDENTIFIER
||lookAhead.getType()==TokenType.LPAREN
||lookAhead.getType()==TokenType.INTEGER_LITERAL) {
Boolterm();
Boolexpression_1();
}else {
String errorTypes =TokenType.IDENTIFIER.toString()
+","+TokenType.INTEGER_LITERAL.toString()
+","+TokenType.LPAREN.toString();
parsingError(errorTypes, "Boolexpression");
}
}
private void Boolexpression_1() {
System.out.println("In Boolexpression_1();-----jmzhang-----");
if (lookAhead.getType()==TokenType.LOGICAL_OR) {
matchToken(TokenType.LOGICAL_OR, "Boolexpression_1");
Boolterm();
Boolexpression_1();
}else if (lookAhead.getType()==TokenType.RPAREN
||lookAhead.getType()==TokenType.SEMICOLON
||lookAhead.getType()==TokenType.LOGICAL_AND
||lookAhead.getType()==TokenType.LOGICAL_OR
) {
//match epslin
//follow(E')={')',','}
}else {
String errorTypes =TokenType.LOGICAL_OR.toString();
parsingError(errorTypes, "Boolexpression_1");
}
}
private void Boolterm() {
System.out.println("In Boolterm();-----jmzhang-----");
if(lookAhead.getType()==TokenType.IDENTIFIER
||lookAhead.getType()==TokenType.LPAREN
||lookAhead.getType()==TokenType.INTEGER_LITERAL){
Boolfactor();
Boolterm_1();
}else {
String errorTypes =TokenType.IDENTIFIER.toString()
+","+TokenType.INTEGER_LITERAL.toString()
+","+TokenType.LPAREN.toString();
parsingError(errorTypes, "Boolterm");
}
}
private void Boolterm_1() {
System.out.println("In Boolterm_1();-----jmzhang-----");
if (lookAhead.getType()==TokenType.LOGICAL_AND) {
matchToken(TokenType.LOGICAL_AND, "Boolterm_1");
Boolfactor();
Boolterm_1();
}else if (lookAhead.getType()==TokenType.LOGICAL_OR
||lookAhead.getType()==TokenType.RPAREN
||lookAhead.getType()==TokenType.SEMICOLON) {
//match e[slion
//follow(T')={'+','-',')',',')
}else {
String errorTypes =TokenType.LOGICAL_AND.toString()
+","+TokenType.LOGICAL_OR.toString()
+","+TokenType.RPAREN.toString()
+","+TokenType.SEMICOLON.toString();
parsingError(errorTypes, "Boolterm_1");
}
}
private void Boolfactor() {
System.out.println("In Boolfactor();-----jmzhang-----");
if (lookAhead.getType()==TokenType.LOGICAL_NOT) {
matchToken(TokenType.LOGICAL_NOT, "Boolfactor");
Boolexpression();
}else if (lookAhead.getType()==TokenType.BOOL_TRUE) {
matchToken(TokenType.BOOL_TRUE, "Boolfactor");
}else if (lookAhead.getType()==TokenType.BOOL_FALSE) {
matchToken(TokenType.BOOL_FALSE, "Boolfactor");
}else {
relationlExpression();
}
}
private void relationlExpression() {
System.out.println("In relationlExpression();-----jmzhang-----");
expression();
relationlExpressionOperator();
expression();
}
private void relationlExpressionOperator() {
System.out.println("In relationlExpressionOperator();-----jmzhang-----");
if (lookAhead.getType()==TokenType.LESS) {
matchToken(TokenType.LESS, "relationlExpressionOperator");
}else if (lookAhead.getType()==TokenType.GREATER) {
matchToken(TokenType.GREATER, "relationlExpressionOperator");
}else if (lookAhead.getType()==TokenType.LESS_EQUAL) {
matchToken(TokenType.LESS_EQUAL, "relationlExpressionOperator");
}else if (lookAhead.getType()==TokenType.GREATER_EQUAL) {
matchToken(TokenType.GREATER_EQUAL, "relationlExpressionOperator");
}else if (lookAhead.getType()==TokenType.NOT_EQUAL) {
matchToken(TokenType.NOT_EQUAL, "relationlExpressionOperator");
}else if(lookAhead.getType()==TokenType.EQUAL) {
matchToken(TokenType.EQUAL, "relationlExpressionOperator");
}else {
}
}
private void ifStatement() {
System.out.println("In ifStatement();-----jmzhang-----");
matchToken(TokenType.KEY_IF, "ifStatement");
matchToken(TokenType.LPAREN, "ifStatement");
Boolexpression();
matchToken(TokenType.RPAREN, "ifStatement");
matchToken(TokenType.LBRACKET, "ifStatement");
Sequence();
matchToken(TokenType.RBRACKET, "ifStatement");
if(lookAhead.getType()==TokenType.KEY_ELSE){
OptionalElse();}
}
private void OptionalElse() {
System.out.println("In OptionalElse();-----jmzhang-----");
if(lookAhead.getType()==TokenType.KEY_ELSE){
System.out.println("In OptionalElse();-----jmzhang-----1");
matchToken(TokenType.KEY_ELSE, "OptionalElse");
matchToken(TokenType.LBRACKET, "OptionalElse");
Sequence();
matchToken(TokenType.RBRACKET, "OptionalElse");
}else if (
lookAhead.getType()==TokenType.RPAREN
||lookAhead.getType()==TokenType.SEMICOLON
||lookAhead.getType()==TokenType.LESS
||lookAhead.getType()==TokenType.GREATER
||lookAhead.getType()==TokenType.LESS_EQUAL
||lookAhead.getType()==TokenType.GREATER_EQUAL
||lookAhead.getType()==TokenType.NOT_EQUAL
||lookAhead.getType()==TokenType.EQUAL
||lookAhead.getType()==TokenType.LOGICAL_AND
||lookAhead.getType()==TokenType.LOGICAL_OR
||lookAhead.getType()==TokenType.IDENTIFIER) {
//match epslion
System.out.println("In OptionalElse();-----jmzhang-----2");
}else {
System.out.println("In OptionalElse();-----jmzhang-----3");
String errorTypes =TokenType.RPAREN.toString()
+","+TokenType.SEMICOLON.toString();
parsingError(errorTypes, "OptionalElse");
}
}
/**
*
* assignmentStatement =IDENTIFIER ASSIGN expression SEMICOLON
* A->id = E;
* 方法名：assignmentStatement
* 创建人：xrzhang
* 时间：2018年5月16日-下午8:56:26
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
private void assignmentStatement() {
System.out.println("In assignmentStatement();-----jmzhang-----");
if (lookAhead.getType()==TokenType.IDENTIFIER) {
matchToken(TokenType.IDENTIFIER, "assignmentStatement");
matchToken(TokenType.ASSIGN, "assignmentStatement");
expression();
matchToken(TokenType.SEMICOLON, "assignmentStatement");
}else {
String errorTypes=TokenType.IDENTIFIER.toString();
parsingError(errorTypes, "assignmentStatement");
}
}
/**
*
* expression = term expression_1
* E->TE'
* 方法名：expression
* 创建人：xrzhang
* 时间：2018年5月16日-下午9:00:40
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
private void expression() {
System.out.println("In expression();-----jmzhang-----");
if (lookAhead.getType()==TokenType.IDENTIFIER
||lookAhead.getType()==TokenType.LPAREN
||lookAhead.getType()==TokenType.INTEGER_LITERAL) {
term();
expression_1();
}else {
String errorTypes =TokenType.IDENTIFIER.toString()
+","+TokenType.INTEGER_LITERAL.toString()
+","+TokenType.LPAREN.toString();
parsingError(errorTypes, "expression");
}
}
/**
*
* expression_1=PLUS term expression_1 | MINUS term expression_1 | epslin
* E'->TE' | -TE' | ε
* 方法名：expression_1
* 创建人：xrzhang
* 时间：2018年5月16日-下午9:06:26
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
private void expression_1() {
System.out.println("In expression_1();-----jmzhang-----");
if (lookAhead.getType()==TokenType.PLUS) {
System.out.println("In expression_1();-----jmzhang-----1");
matchToken(TokenType.PLUS, "expression_1");
term();
expression_1();
}else if (lookAhead.getType()==TokenType.MINUS) {
System.out.println("In expression_1();-----jmzhang-----2");
matchToken(TokenType.MINUS, "expression_1");
term();
expression_1();
}else if (lookAhead.getType()==TokenType.RPAREN
||lookAhead.getType()==TokenType.SEMICOLON
||lookAhead.getType()==TokenType.LESS
||lookAhead.getType()==TokenType.GREATER
||lookAhead.getType()==TokenType.LESS_EQUAL
||lookAhead.getType()==TokenType.GREATER_EQUAL
||lookAhead.getType()==TokenType.NOT_EQUAL
||lookAhead.getType()==TokenType.EQUAL
||lookAhead.getType()==TokenType.LOGICAL_AND
||lookAhead.getType()==TokenType.LOGICAL_OR
) {
System.out.println("In expression_1();-----jmzhang-----3");
//match epslin
//follow(E')={')',','}
}else {
System.out.println("In expression_1();-----jmzhang-----4");
String errorTypes =TokenType.PLUS.toString()
+","+TokenType.MINUS.toString()
+","+TokenType.RPAREN.toString()
+","+TokenType.SEMICOLON.toString();
parsingError(errorTypes, "expression_1");
}
}
/**
*
* term=factor term_1
* T->FT'
* 方法名：term
* 创建人：xrzhang
* 时间：2018年5月16日-下午9:16:51
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
private void term() {
System.out.println("In term();-----jmzhang-----");
if(lookAhead.getType()==TokenType.IDENTIFIER
||lookAhead.getType()==TokenType.LPAREN
||lookAhead.getType()==TokenType.INTEGER_LITERAL){
factor();
term_1();
}else {
String errorTypes =TokenType.IDENTIFIER.toString()
+","+TokenType.INTEGER_LITERAL.toString()
+","+TokenType.LPAREN.toString();
parsingError(errorTypes, "term");
}
}
/**
*
* term_1=MULT factor term_1 | DIV factor term_1 | MOD factor term_1 | epslin
* T'->*FT' | /FT' |%FT'|ε
* 方法名：term_1
* 创建人：xrzhang
* 时间：2018年5月16日-下午9:20:00
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
private void term_1() {
System.out.println("In term_1();-----jmzhang-----");
if (lookAhead.getType()==TokenType.TIMES) {
matchToken(TokenType.TIMES, "term_1");
factor();
term_1();
}else if (lookAhead.getType()==TokenType.DIVIDE) {
matchToken(TokenType.DIVIDE, "term_1");
factor();
term_1();
}else if (lookAhead.getType()==TokenType.REMAINDER) {
matchToken(TokenType.REMAINDER, "term_1");
factor();
term_1();
}else if (lookAhead.getType()==TokenType.PLUS
||lookAhead.getType()==TokenType.MINUS
||lookAhead.getType()==TokenType.RPAREN
||lookAhead.getType()==TokenType.SEMICOLON
||lookAhead.getType()==TokenType.LESS
||lookAhead.getType()==TokenType.GREATER
||lookAhead.getType()==TokenType.LESS_EQUAL
||lookAhead.getType()==TokenType.GREATER_EQUAL
||lookAhead.getType()==TokenType.NOT_EQUAL
||lookAhead.getType()==TokenType.EQUAL
||lookAhead.getType()==TokenType.LOGICAL_AND
||lookAhead.getType()==TokenType.LOGICAL_OR
) {
//match e[slion
//follow(T')={'+','-',')',',')
}else {
String errorTypes =TokenType.TIMES.toString()
+","+TokenType.DIVIDE.toString()
+","+TokenType.REMAINDER.toString()
+","+TokenType.PLUS.toString()
+","+TokenType.MINUS.toString()
+","+TokenType.RPAREN.toString()
+","+TokenType.SEMICOLON.toString();
parsingError(errorTypes, "term_1");
}
}
/**
*
* factor = LPAREN expression RPAREN | IDENTIFER|INTEGER_LITERAL
* F->(E)|id| number
* 方法名：factor
* 创建人：xrzhang
* 时间：2018年5月16日-下午9:29:47
* 邮件：[email protected] void
* @exception
* @since 1.0.0
*/
private void factor() {
System.out.println("In factor();-----jmzhang-----");
if (lookAhead.getType()==TokenType.LPAREN) {
matchToken(TokenType.LPAREN, "factor");
expression();
matchToken(TokenType.RPAREN, "factor");
}else if (lookAhead.getType()==TokenType.IDENTIFIER) {
matchToken(TokenType.IDENTIFIER, "factor");
}else if (lookAhead.getType()==TokenType.INTEGER_LITERAL) {
matchToken(TokenType.INTEGER_LITERAL, "factor");
}else {
String errorTypes =TokenType.LPAREN.toString()
+","+TokenType.IDENTIFIER.toString()
+","+TokenType.INTEGER_LITERAL.toString();
parsingError(errorTypes, "factor");
}
}
}