我有这个简单的语法:
word = Word(alphanums + '_')
with_stmt = Suppress('with') + OneOrMore(Group(word('key') + Suppress('=') + word('value')))('overrides')
using_stmt = Suppress('using') + Regex('id-[0-9a-f]{8}')('id')
modifiers = Optional(with_stmt('with_stmt')) & Optional(using_stmt('using_stmt'))
pattern = StringStart() + modifiers + StringEnd()
似乎 Optional() 和 Optional()
错误地允许多次重复任何一个 modifier
,并且只标记最后一个:
>>> print dict(pattern.parseString('with foo=bar bing=baz using id-deadbeef using id-feedfeed'))
{
'with_stmt': (
[
(['foo', 'bar'], {'value': [('bar', 1)], 'key': [('foo', 0)]}),
(['bing', 'baz'], {'value': [('baz', 1)], 'key': [('bing', 0)]})
],
{'overrides':
[(([
(['foo', 'bar'], {'value': [('bar', 1)], 'key': [('foo', 0)]}),
(['bing', 'baz'], {'value': [('baz', 1)], 'key': [('bing', 0)]})
], {}), 0)]
}
),
'overrides':
(
[(['foo', 'bar'], {'value': [('bar', 1)], 'key': [('foo', 0)]}),
(['bing', 'baz'], {'value': [('baz', 1)], 'key': [('bing', 0)]})], {}
),
'id': (['id-deadbeef', 'id-feedfeed'], {}),
'using_stmt': (['id-deadbeef', 'id-feedfeed'], {'id': [('id-deadbeef', 0), ('id-feedfeed', 1)]})
}
using_stmt
同时匹配 id-deadbeef
Và id-feedfeed
而不是在 using id-feedfeed
处抛出错误>.
奇怪的是,如果使 modifiers
成为非可选的,那么重复问题就会消失并且解析会按预期失败:
>>> dict(pattern.parseString('with foo=bar bing=baz using id-deadbeef using id-feedfeed'))
Traceback (cuộc gọi gần đây nhất):
File "parse.py", line 10, in
print dict(pattern.parseString('with foo=bar bing=baz using id-deadbeef using id-feedfeed'))
File "/path/to/lib/python2.7/site-packages/pyparsing.py", line 1139, in parseString
raise exc
pyparsing.ParseException: Expected end of text (at char 40), (line:1, col:41)
切换到 +
thay vì &
也会导致它按预期失败。 with_stmt
表现出同样的问题,将其设为非可选也可以解决此问题。
将一个模式标记为允许在 Each()
中重复的模式是什么意思?
Tôi là một lập trình viên xuất sắc, rất giỏi!