如何显示ANTLR树GUI

Question

如果你有这样的代码,如控制台还是摇摆,你如何显示AST GUI？我的ANTLR是版本3.

CharStream stream = new ANTLRStringStream("program XLSample1 =\n" + 
            "constant one : Integer := 1;\n" + 
            "constant two : Integer := 2;\n" + 
            "var a, b,c : Integer := 42;\n" + 
            "begin\n" + 
            " x:= (12 + 6) - (7 * 41) - x mod y;\n" + 
            " y := 21;\n" + 
            "\n" + 
            "if x < 10 then\n" + 
            "  y :=2;\n" + 
            "  elseif x < 20 then\n" + 
            "  y := 20;\n" + 
            "  else\n" + 
            "  y := 30;\n" + 
            "end if; \n" + 
            "end XLSample1.");
    SampleLexer lexer  = new SampleLexer(stream);   
    TokenStream tokenStream = new CommonTokenStream(lexer);
    SampleParser parser = new SampleParser(tokenStream);
    parser.program();       
    System.out.println("OK");       
}

Answer 1

我喜欢ANLTR,所以我试着回答它.

使用Antlr V4(对于V3尝试找出类似的API),要显示一个gui AST,可以使用org.antlr.v4.runtime.tree.gui.TreeViewer.

你可以从ANTLR的网站上获得Hello演示,一旦你得到它,运行这个简单的演示:

import java.util.Arrays;
import javax.swing.JFrame;
import javax.swing.JPanel;

import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.TokenStream;
import org.antlr.v4.runtime.tree.ParseTree;
import org.antlr.v4.runtime.tree.gui.TreeViewer;

/**
 * A simple demo to show AST GUI with ANTLR
 * @see http://www.antlr.org/api/Java/org/antlr/v4/runtime/tree/gui/TreeViewer.html
 * 
 * @author wangdq
 * 2014-5-24
 *
 */
public class HelloTestDrive {
    public static void main(String[] args) {
        //prepare token stream
        CharStream stream = new ANTLRInputStream("hello antlr");
        HelloLexer lexer  = new HelloLexer(stream);   
        TokenStream tokenStream = new CommonTokenStream(lexer);
        HelloParser parser = new HelloParser(tokenStream);
        ParseTree tree = parser.r(); 

        //show AST in console
        System.out.println(tree.toStringTree(parser));

        //show AST in GUI
        JFrame frame = new JFrame("Antlr AST");
        JPanel panel = new JPanel();
        TreeViewer viewr = new TreeViewer(Arrays.asList(
                parser.getRuleNames()),tree);
        viewr.setScale(1.5);//scale a little
        panel.add(viewr);
        frame.add(panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(200,200);
        frame.setVisible(true);
    }
}

然后,您将在控制台中获得AST打印并在JFrame中显示.更多细节,请参考ANLTR API.

确保您的语法正常工作,然后您可以修改此演示以满足您的需求.

ANTLR 4的更新:已从ANTLR 4工具org.antlr.v4.runtime.tree.gui.TreeViewer转移到JFrame包.