从Java生成Antlr4 Lexer

我知道，大多数人让Antlr从命令行生成，但我想从Java调用它。我也不能调用工具类的

main

，因为该类使用

System.exit

，因为这也会退出我的程序

到目前为止，我尝试了以下内容：

        String g4Content = "My Grammar Content";            

        String[] arg0 = {pathOfG4File, "-package", "mypackage"};

        Tool tool = new Tool(arg0);

        GrammarRootAST ast = tool.parseGrammarFromString(g4Content)
        Grammar grammar = tool.createGrammar(ast);

        tool.process(grammar, true)

我得到以下例外情况：

java.lang.NoSuchMethodError: org.antlr.v4.parse.BlockSetTransformer.inContext(Ljava/lang/String;)Z
at org.antlr.v4.parse.BlockSetTransformer.setAlt(BlockSetTransformer.java:467)
at org.antlr.v4.parse.BlockSetTransformer.topdown(BlockSetTransformer.java:370)
at org.antlr.v4.parse.BlockSetTransformer.topdown(BlockSetTransformer.java:24)
at org.antlr.runtime.tree.TreeRewriter$2.rule(TreeRewriter.java:108)
at org.antlr.runtime.tree.TreeRewriter.applyOnce(TreeRewriter.java:61)
at org.antlr.runtime.tree.TreeRewriter$1.pre(TreeRewriter.java:92)
at org.antlr.runtime.tree.TreeVisitor.visit(TreeVisitor.java:28)
at org.antlr.runtime.tree.TreeVisitor.visit(TreeVisitor.java:33)
at org.antlr.runtime.tree.TreeVisitor.visit(TreeVisitor.java:33)
at org.antlr.runtime.tree.TreeVisitor.visit(TreeVisitor.java:33)
at org.antlr.runtime.tree.TreeVisitor.visit(TreeVisitor.java:33)
at org.antlr.runtime.tree.TreeRewriter.downup(TreeRewriter.java:95)
at org.antlr.runtime.tree.TreeRewriter.downup(TreeRewriter.java:86)
at org.antlr.v4.tool.GrammarTransformPipeline.reduceBlocksToSets(GrammarTransformPipeline.java:89)
at org.antlr.v4.tool.GrammarTransformPipeline.process(GrammarTransformPipeline.java:78)
at org.antlr.v4.Tool.process(Tool.java:360)
at java.util.Collections$UnmodifiableCollection.forEach(Collections.java:1080)
at de.ustutt.sidewise.editor.generator.BnfModelGenerator.doGenerate(BnfModelGenerator.java:53)
at org.eclipse.xtext.builder.BuilderParticipant.handleChangedContents(BuilderParticipant.java:524)
at org.eclipse.xtext.builder.BuilderParticipant.handleChangedContents(BuilderParticipant.java:513)
at org.eclipse.xtext.builder.BuilderParticipant.doGenerate(BuilderParticipant.java:498)
at org.eclipse.xtext.builder.BuilderParticipant.doBuild(BuilderParticipant.java:263)
at org.eclipse.xtext.builder.BuilderParticipant.build(BuilderParticipant.java:221)
at org.eclipse.xtext.builder.impl.RegistryBuilderParticipant$DeferredBuilderParticipant.build(RegistryBuilderParticipant.java:161)
at org.eclipse.xtext.builder.impl.RegistryBuilderParticipant.build(RegistryBuilderParticipant.java:69)
at org.eclipse.xtext.builder.impl.XtextBuilder.doBuild(XtextBuilder.java:252)
at org.eclipse.xtext.builder.impl.XtextBuilder.fullBuild(XtextBuilder.java:280)
at org.eclipse.xtext.builder.impl.XtextBuilder.build(XtextBuilder.java:117)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:734)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:205)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:245)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:300)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:303)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:359)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:382)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:144)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:235)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

---

这是一个已知的工作实现：

private void compileGrammar(IResource resource, IProgressMonitor monitor) {
    if (resource != null && resource instanceof IFile && (resource.getName().endsWith(".g4"))) {
        IFile file = (IFile) resource;

        try {
            String outputDirectory = determineBuildFolder(file).toString();
            Log.info(this, "Building  [file=" + file.getFullPath() + "]");
            Log.info(this, "Output to [dir= " + outputDirectory + "]");
            monitor.worked(1);

            Tool tool = new Tool(new String[] { "-o", outputDirectory });
            tool.removeListeners();
            ErrorListener toolErrs = new ErrorListener();
            tool.addListener(toolErrs);
            monitor.worked(1);

            // Prep and process the grammar file
            String loc = file.getLocation().toPortableString();
            Grammar g = tool.loadGrammar(loc);
            tool.process(g, true);
            monitor.worked(1);

            if (toolErrs.hasErrors()) {
                for (ANTLRMessage err : toolErrs.getErrList()) {
                    Log.error(this, err.toString());
                    AntlrDTCore.getDefault().showConsoleMessage(err.toString(), AntlrDTCore.MSG_ERROR);
                }
            }
            if (toolErrs.hasWarnings()) {
                for (ANTLRMessage warn : toolErrs.getWarnList()) {
                    Log.warn(this, warn.toString());
                    AntlrDTCore.getDefault().showConsoleMessage(warn.toString(), AntlrDTCore.MSG_WARNING);
                }
            }

            postCompileCleanup(file, monitor);
            monitor.worked(1);
        } catch (Exception e) {
            Log.error(this, "Build failed.", e);
        }
    }
}

---

顺便说一句，看起来您使用的是XText-上次我检查它使用的是修改后的Antlr3实现

实际上，我建议在构建过程中使用Maven或类似的构建来构建解析器/词法分析器tool@SeanPatrickFloyd谢谢你的评论，但这对我来说是不可能的。我动态生成.g4文件，并且必须从该文件生成Lexer。这仍然可以。要么在生命周期的早期生成语法，要么在单独的project@SeanPatrickFloyd嗯，我需要在运行时执行此操作。我不确定，但在运行时使用Maven或Ant对我来说似乎是错误的。没有别的解决办法吗？不，你是对的，我也觉得不对。但在运行时生成Lexer也是如此：-（感谢您的评论。本质上，这与我上面的代码相同。我发现了我的问题，它与依赖项有关，但没有得到正确解决。XText使用Antlr3，但不是在运行时，而是在运行Workfow并在第一次运行时下载它时。因此，我不认为在这种情况下依赖XText的Antlr是不正确的。）好主意。