如何使用 antlr4 访客
2022-09-03 14:16:43
我是蚂蚁的初学者。我试图在我的代码中使用访问者,并按照网络上的说明进行操作。但是,我发现访问者根本没有输入我创建的方法。谁能告诉我我做错了什么?
这是我的访客:
import java.util.LinkedList;
import org.antlr.v4.runtime.misc.NotNull;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author Sherwood
*/
public class ExtractMicroBaseVisitor extends MicroBaseVisitor<Integer> {
//LinkedList<IR> ll = new LinkedList<IR>();
//MicroParser parser;
//System.out.println("11");
@Override
public Integer visitPgm_body(@NotNull MicroParser.Pgm_bodyContext ctx){
System.out.println(ctx.getText());
return 467;
}
@Override
public Integer visitProgram(@NotNull MicroParser.ProgramContext ctx){
System.out.println("11");
return 456;
}
}
如您所见,当输入方法“visitProgram”时,标准输出应打印 11。但是输出屏幕没有给我任何东西(空类型)。
这是我的主代码:
import java.io.IOException;
import org.antlr.v4.runtime.*;
import org.antlr.v4.runtime.tree.*;
/**
*
* @author Sherwood
*/
public class Compiler {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
//SymbolTable table = new SymbolTable();
try {
ANTLRFileStream reader = new ANTLRFileStream("TestCases/step4_testcase3.micro");
MicroLexer lexer = new MicroLexer((CharStream)reader);
TokenStream tokens = new CommonTokenStream(lexer);
MicroParser parser = new MicroParser(tokens);
parser.setErrorHandler(new MyErrorStrategy());
ParseTree tree = parser.program();
//ParseTreeWalker walker = new ParseTreeWalker(); // create standard walker
//ExtractMicroBaseListener extractor = new ExtractMicroBaseListener(parser);
//walker.walk(extractor, tree); // initiate walk of tree with listener
ExtractMicroBaseVisitor visitor = new ExtractMicroBaseVisitor();
int t = visitor.visit(tree);
//for(String str : extractor.table.checkDuplicate()){
// System.out.println("SHADOW WARNING " + str);
//}
//System.out.println(extractor.table.checkDuplicate().toString());
//System.out.println(extractor.table.toString());
//System.out.println("Accepted");
}catch (IOException e) {
System.out.println("Not Accepted");
}catch(IllegalArgumentException e){
System.out.println(e.getMessage());
}
}
}
这是我的语法文件(部分):
grammar Micro;
options {
language = Java;
}
//Program
program : ('PROGRAM' id 'BEGIN' pgm_body 'END')
;
id : IDENTIFIER;
pgm_body : (decl func_declarations);
decl : (string_decl_list | var_decl_list)* ;