使用简约的Python库解析多行文本

Question

我正在尝试使用python简约库来解析多行文本。我已经玩了一段时间了，不知道如何有效地处理换行符。下面是一个例子。下面的行为是有意义的。我在节俭的问题中看到了来自Erik Rose的this comment，但我不知道如何在没有错误的情况下实现它。谢谢你在这里给我的建议。

singleline_text = '''\
FIRST   something cool'''

multiline_text = '''\
FIRST   something very
        cool
SECOND  more awesomeness        
'''

grammar = Grammar(
    """
    bin           = ORDER spaces description
    ORDER         = 'FIRST' / 'SECOND'
    spaces        = ~'\s*'
    description   = ~'[A-z0-9 ]*'
    """)

对于单行输出，工作正常，print(grammar.parse(singleline_text))提供：

<Node called "bin" matching "FIRST   something cool">
    <Node called "ORDER" matching "FIRST">
        <Node matching "FIRST">
    <RegexNode called "spaces" matching "   ">
    <RegexNode called "description" matching "something cool">

但是multiline给出了问题，而我无法根据上面的链接解决，print(grammar.parse(multiline_text))给出了：

---------------------------------------------------------------------------
IncompleteParseError                      Traceback (most recent call last)
<ipython-input-123-c346891dc883> in <module>()
----> 1 print(grammar.parse(multiline_text))

/Users/me/anaconda3/lib/python3.6/site-packages/parsimonious/grammar.py in parse(self, text, pos)
    121         """
    122         self._check_default_rule()
--> 123         return self.default_rule.parse(text, pos=pos)
    124 
    125     def match(self, text, pos=0):

/Users/me/anaconda3/lib/python3.6/site-packages/parsimonious/expressions.py in parse(self, text, pos)
    110         node = self.match(text, pos=pos)
    111         if node.end < len(text):
--> 112             raise IncompleteParseError(text, node.end, self)
    113         return node
    114 

IncompleteParseError: Rule 'bin' matched in its entirety, but it didn't consume all the text. The non-matching portion of the text begins with '
        cool
SECOND' (line 1, column 23).

有一件事我试过了，但没有奏效：

grammar2 = Grammar(
    """
    bin           = ORDER spaces description newline
    ORDER         = 'FIRST' / 'SECOND'
    spaces        = ~'\s*'
    description   = ~'[A-z0-9 \n]*'
    newline       = ~r'#[^\r\n]*'
    """)

print(grammar2.parse(multiline_text))

(从211行堆栈跟踪中截断)：

ERROR:root:An unexpected error occurred while tokenizing input
The following traceback may be corrupted or invalid
The error message is: ('EOF in multi-line string', (1, 4))

---------------------------------------------------------------------------
SyntaxError                               Traceback (most recent call last)

...


VisitationError: SyntaxError: EOL while scanning string literal (<unknown>, line 1)

Parse tree:
<Node called "spaceless_literal" matching "'[A-z0-9 
]*'">  <-- *** We were here. ***
    <RegexNode matching "'[A-z0-9 
    ]*'">

Answer 1

看起来你需要在你的语法中重复bin元素：

grammar = Grammar(
    r"""
    one           = bin +
    bin           = ORDER spaces description newline 
    ORDER         = 'FIRST' / 'SECOND'
    newline       = ~"\n*"
    spaces        = ~"\s*"
    description   = ~"[A-z0-9 ]*"i
    """)

有了它，您就可以解析如下内容：

multiline_text = '''\
FIRST   something very cool
SECOND  more awesomeness      
SECOND  even better
'''