我使用来自ANTLR wiki的语法Java.g为Java源文件生成词法分析器和解析器。然后使用以下代码生成abstract syntax tree (AST)。
ANTLRInputStream input = new ANTLRInputStream(new FileInputStream(fileName));
JavaLexer lexer = new JavaLexer(input); // create lexer
// create a buffer of tokens pulled from the lexer
CommonTokenStream tokens = new CommonTokenStream(lexer);
JavaParser parser = new JavaParser(tokens); // create parser
JavaParser.javaSource_return r = parser.javaSource(); // parse rule 'javaSource'
/*RuleReturnScope result = parser.compilationUnit();
CommonTree t = (CommonTree) result.getTree();*/
// WALK TREE
// get the tree from the return structure for rule prog
CommonTree t = (CommonTree)r.getTree();
然后修改AST。例如,替换"文件文件=新文件(filepath,fileType);"至 " S3Object _file = new S3Object(_fileName);"通过修改AST节点。在此之后,我想将此AST转换为java源代码。我修改JavaTreeParser.g并编写一个stringtemplate并使用以下方法获取java源代码:
FileReader groupFileR = new FileReader("src/com/googlecode/zcg/templates/JavaTemplate.stg");
StringTemplateGroup templates = new StringTemplateGroup(groupFileR);
groupFileR.close();
// create a stream of tree nodes from AST built by parser
CommonTreeNodeStream nodes = new CommonTreeNodeStream(t);
// tell it where it can find the token objects
nodes.setTokenStream(tokens);
JavaTreeParser walker = new JavaTreeParser(nodes); // create the tree Walker
walker.setTemplateLib(templates); // where to find templates
// invoke rule prog, passing in information from parser
JavaTreeParser.javaSource_return r2 = walker.javaSource();
// EMIT BYTE CODES
// get template from return values struct
StringTemplate output = (StringTemplate)r2.getTemplate();
System.out.println(output.toString()); // render full template
如果我没有修改AST,它将正确获取java源代码,但在我修改AST后,它没有获得正确的java源代码(AST被正确修改)。例如,如果我输入以下源代码并转换为AST,则修改"文件文件=新文件(filepath,fileType);" to" S3Object _file = new S3Object(_fileName);":
public void methodname(String address){
String filepath = "file";
int fileType = 3;
File file = new File(filepath, fileType);
}
结果将如下:
public void methodname( String address)
{
String filepath="file";
int fileType=3;
methodname (Stringaddress){Stringfilepath;//it's not what I wanted
}
我做错了吗?我有更合适的方法来解决这个问题吗?
答案 0 :(得分:1)
遗憾的是,我不建议通过重写抽象语法树来完成源代码翻译;尝试使用解析树。如果我记得ANTLR 3也可以轻松生成。 叔