我想在 Python 中使用 ANTLR 构建一个 Java 解析器。
我从 ANTLR 存储库下载了语法:
Lexer :https://github.com/antlr/grammars-v4/blob/master/java/java/JavaLexer.g4 https://github.com/antlr/grammars-v4/blob/master/java/java/JavaLexer.g4
Parser: https://github.com/antlr/grammars-v4/blob/master/java/java/JavaParser.g4 https://github.com/antlr/grammars-v4/blob/master/java/java/JavaParser.g4
然后我使用 script.bat 生成我需要的 python 代码:
java -jar antlr-4.8-complete.jar -Dlanguage=Python3 Java8Lexer.g4
java -jar antlr-4.8-complete.jar -Dlanguage=Python3 Java8Parser.g4
antlr-4.8-complete.jar
在这里下载:https://www.antlr.org/download/antlr-4.8-complete.jar https://www.antlr.org/download/antlr-4.8-complete.jar
这生成了以下文件列表:
- Java8Lexer.interp
- Java8Lexer.py
- Java8Lexer.tokens
- Java8Parser.interp
- Java8Parser.py
- Java8Parser.tokens
- Java8ParserListener.py
然后我写了这段代码来解析java文件:
import antlr4
from antlr4 import *
from java.antlr_unit2 import Java8Parser, Java8Lexer
def main():
code = open('test.txt', 'r').read()
lexer = Java8Lexer.Java8Lexer(antlr4.InputStream(code))
stream = antlr4.CommonTokenStream(lexer)
parser = Java8Parser.Java8Parser(stream)
tree = parser.expression()
print (tree)
if __name__ == '__main__':
main()
我的测试java代码test.txt
是这样的:
package org.jabref.gui.fieldeditors;
import java.util.ArrayList;
/**
* This class contains some code
*/
public class TextInputControlBehavior {
private static final boolean SHOW_HANDLES = Properties.IS_TOUCH_SUPPORTED && !OS.OS_X;
}
由于这太短了,这里是我要解析的代码示例:https://pastebin.com/KNxfasKQ https://pastebin.com/KNxfasKQ
当我运行此代码时,我得到:
line 1:0 extraneous input 'package' expecting {'boolean', 'byte', 'char', 'double', 'float', 'int', 'long', 'new', 'short', 'super', 'this', 'void', IntegerLiteral, FloatingPointLiteral, BooleanLiteral, CharacterLiteral, StringLiteral, 'null', '(', '!', '~', '++', '--', '+', '-', Identifier, '@'}
[]
难道我做错了什么?我没有写语法,我只是从 ANTLR 存储库中获取它。
EDIT: 帕维尔·斯米尔诺夫的回答对我有帮助,现在我没有收到警告。但现在程序看起来真的很慢,我得到一棵空树作为输出。
SOLVED: 我正在打印tree
但我不得不print(tree.toStringTree(recog=parser))
所以最终的代码是:
import antlr4
from antlr4 import *
from java.antlr_unit2 import Java8Parser, Java8Lexer
def main():
code = open('test.txt', 'r').read()
lexer = Java8Lexer.Java8Lexer(antlr4.InputStream(code))
stream = antlr4.CommonTokenStream(lexer)
parser = Java8Parser.Java8Parser(stream)
tree = parser.compilationUnit()
print(tree.toStringTree(recog=parser))
if __name__ == '__main__':
main()