public class CallGraphListener extends CymbolBaseListener {
  private Graph graph = new Graph();
  String currentFunctionName = null;

  @Override
  public void enterFunctionDecl(CymbolParser.FunctionDeclContext ctx) {
    currentFunctionName = ctx.ID().getText();
    graph.addNode(currentFunctionName);
  }

  @Override
  public void enterCall(CymbolParser.CallContext ctx) {
    String callee = ctx.ID().getText();
    graph.addEdge(currentFunctionName, callee);
  }

  public Graph getGraph() {
    return this.graph;
  }
}

public class CalcListener extends CymbolBaseListener {
  private ParseTreeProperty<Integer> values = new ParseTreeProperty<>();

  @Override
  public void exitExprStat(CymbolParser.ExprStatContext ctx) {
      //退出表达式节点
      //打印表达式结果，值等于子节点值
    System.out.println(ctx.expr().getText() + 
                       " = " + values.get(ctx.expr()));
  }

  @Override
  public void exitAddSub(CymbolParser.AddSubContext ctx) {
      //左节点+/-右节点
      //是+还是-已经标注
      //左节点和右节点也有标注
    int lvalue = values.get(ctx.lhs);
    int rvalue = values.get(ctx.rhs);

    if (ctx.op.getType() == ADD) {
      values.put(ctx, lvalue + rvalue);
    } else {
      values.put(ctx, lvalue - rvalue);
    }
  }

  @Override
  public void exitParens(CymbolParser.ParensContext ctx) {
     //(expr) expr
     //形同去括号，从子节点中取出放到括号节点
     //expr为子节点
    values.put(ctx, values.get(ctx.expr()));
  }

  @Override
  public void exitNegate(CymbolParser.NegateContext ctx) {
      //从子节点取值，取负号，标记
    values.put(ctx, -values.get(ctx.expr()));
  }

  @Override
  public void exitInt(CymbolParser.IntContext ctx) {
     //把值取出来，放到相应节点
     //ctx当前节点
    values.put(ctx, Integer.valueOf(ctx.INT().getText()));
  }

  @Override
  public void exitPower(CymbolParser.PowerContext ctx) {
      //幂运算
      //同理
    int lvalue = values.get(ctx.lhs);
    int rvalue = values.get(ctx.rhs);

    values.put(ctx, Integer.parseInt(String.valueOf
                                     (Math.pow(lvalue, rvalue))));
  }

  @Override
  public void exitMultDiv(CymbolParser.MultDivContext ctx) {
      // * or /
    int lvalue = values.get(ctx.lhs);
    int rvalue = values.get(ctx.rhs);

    if (ctx.op.getType() == MUL) {
      values.put(ctx, lvalue * rvalue);
    } else {
      values.put(ctx, lvalue / rvalue);
    }
  }
}

package calc;

import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.CharStreams;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.tree.ParseTree;
import org.antlr.v4.runtime.tree.ParseTreeWalker;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;

import calc.listener.CalcListener;
import cymbol.CymbolLexer;
import cymbol.CymbolParser;

public class Calculator {
  public static void main(String[] args) throws IOException {
    InputStream is = new FileInputStream(Path.of("src/main/antlr/cymbol/cymbol-calculator.txt").toFile());
//    InputStream is = new FileInputStream(Path.of("src/main/antlr/cymbol/cymbol-calc-stat.txt").toFile());
    CharStream cs = CharStreams.fromStream(is);
    CymbolLexer lexer = new CymbolLexer(cs);
    CommonTokenStream tokens = new CommonTokenStream(lexer);

    CymbolParser parser = new CymbolParser(tokens);

    // for CalcListener and cymbol-calculator.txt
    ParseTree tree = parser.prog();
    ParseTreeWalker walker = new ParseTreeWalker();
    CalcListener calcListener = new CalcListener();
    walker.walk(calcListener, tree);

//    for CalcVistor and cymbol-calc-stat.txt
//    ParseTree tree = parser.block();
//    CalcVisitor caclVisitor = new CalcVisitor();
//    caclVisitor.visit(tree);
  }
}