我得到简单的 antlr3 语法MicroXpath并为 Python 构建词法分析器和解析器。
然后我写了一个简单的测试代码:
import antlr3
from XPathLexer import XPathLexer
from XPathParser import XPathParser
def print_level_order(tree, indent):
print('{0}{1}'.format(' '*indent, tree.text, tree.getType()))
for child in tree.getChildren():
print_level_order(child, indent+1)
input = 'descendant::name[class/name[test="x"]="File"]'
char_stream = antlr3.ANTLRStringStream(input)
lexer = XPathLexer(char_stream)
tokens = antlr3.CommonTokenStream(lexer)
parser = XPathParser(tokens)
tree = parser.xPath().tree
print_level_order(tree, 0)
结果:
None
descendant
:
name
[
class
/
name
[
test
=
"x"
]
=
"File"
]
树在哪里?这是一个线性列表!我究竟做错了什么?还是用ANTLR不能建树?