我仍然认为自己是 pyparsing 的新手。我拼凑了 2 个快速语法，但都没有成功完成我想做的事情。我试图想出一个看起来很简单的语法，但事实证明（至少对我来说）并不是那么微不足道。该语言有一个基本定义。它按关键字和正文细分。正文可以跨越多行。关键字位于行首的前 20 个字符左右，但以 ';' 结尾 （没有引号）。所以我拼凑了一个快速演示程序，这样我就可以用几个语法进行测试。但是，当我尝试使用它们时，它们总是得到第一个关键字，但之后没有。
我附上了源代码作为示例和正在发生的输出。尽管这只是测试代码，但出于习惯我做了文档。在下面的示例中，两个关键字是 NOW；最后; 理想情况下，我不希望关键字中包含分号。
有什么想法我应该做些什么来完成这项工作？
from pyparsing import *
def testString(text,grammar):
"""
@summary: perform a test of a grammar
2type text: text
@param text: text buffer for input (a message to be parsed)
@type grammar: MatchFirst or equivalent pyparsing construct
@param grammar: some grammar defined somewhere else
@type pgm: text
@param pgm: typically name of the program, which invoked this function.
@status: 20130802 CODED
"""
print 'Input Text is %s' % text
print 'Grammar is %s' % grammar
tokens = grammar.parseString(text)
print 'After parse string: %s' % tokens
tokens.dump()
tokens.keys()
return tokens
def getText(msgIndex):
"""
@summary: make a text string suitable for parsing
@returns: returns a text buffer
@type msgIndex: int
@param msgIndex: a number corresponding to a text buffer to retrieve
@status: 20130802 CODED
"""
msg = [ """NOW; is the time for a few good ones to come to the aid
of new things to come for it is almost time for
a tornado to strike upon a small hill
when least expected.
lastly; another day progresses and
then we find that which we seek
and finally we will
find our happiness perhaps its closer than 1 or 2 years or not so
""",
'',
]
return msg[msgIndex]
def getGrammar(grammarIndex):
"""
@summary: make a grammar given an index
@type: grammarIndex: int
@param grammarIndex: a number corresponding to the grammar to be retrieved
@Note: a good run will return 2 keys: NOW: and lastly: and each key will have an associated body. The body is all
words and text up to the next keyword or eof which ever is first.
"""
kw = Combine(Word(alphas + nums) + Literal(';'))('KEY')
kw.setDebug(True)
body1 = delimitedList(OneOrMore(Word(alphas + nums)) +~kw)('Body')
body1.setDebug(True)
g1 = OneOrMore(Group(kw + body1))
# ok start defining a new grammar (borrow kw from grammar).
body2 = SkipTo(~kw, include=False)('BODY')
body2.setDebug(True)
g2 = OneOrMore(Group(kw+body2))
grammar = [g1,
g2,
]
return grammar[grammarIndex]
if __name__ == '__main__':
# list indices [ text, grammar ]
tests = {1: [0,0],
2: [0,1],
}
check = tests.keys()
check.sort()
for testno in check:
print 'STARTING Test %d' % testno
text = getText(tests[testno][0])
grammar = getGrammar(tests[testno][1])
tokens = testString(text, grammar)
print 'Tokens found %s' % tokens
print 'ENDING Test %d' % testno
输出如下所示：（使用 python 2.7 和 pyparsing 2.0.1）
STARTING Test 1
Input Text is NOW; is the time for a few good ones to come to the aid
of new things to come for it is almost time for
a tornado to strike upon a small hill
when least expected.
lastly; another day progresses and
then we find that which we seek
and finally we will
find our happiness perhaps its closer than 1 or 2 years or not so
Grammar is {Group:({Combine:({W:(abcd...) ";"}) {{W:(abcd...)}... ~{Combine:({W:(abcd...) ";"})}} [, {{W:(abcd...)}... ~{Combine:({W:(abcd...) ";"})}}]...})}...
Match Combine:({W:(abcd...) ";"}) at loc 0(1,1)
Matched Combine:({W:(abcd...) ";"}) -> ['NOW;']
Match {{W:(abcd...)}... ~{Combine:({W:(abcd...) ";"})}} [, {{W:(abcd...)}... ~{Combine:({W:(abcd...) ";"})}}]... at loc 4(1,5)
Match Combine:({W:(abcd...) ";"}) at loc 161(4,20)
Exception raised:Expected W:(abcd...) (at char 161), (line:4, col:20)
Matched {{W:(abcd...)}... ~{Combine:({W:(abcd...) ";"})}} [, {{W:(abcd...)}... ~{Combine:({W:(abcd...) ";"})}}]... -> ['is', 'the', 'time', 'for', 'a', 'few', 'good', 'ones', 'to', 'come', 'to', 'the', 'aid', 'of', 'new', 'things', 'to', 'come', 'for', 'it', 'is', 'almost', 'time', 'for', 'a', 'tornado', 'to', 'strike', 'upon', 'a', 'small', 'hill', 'when', 'least', 'expected']
Match Combine:({W:(abcd...) ";"}) at loc 161(4,20)
Exception raised:Expected W:(abcd...) (at char 161), (line:4, col:20)
After parse string: [['NOW;', 'is', 'the', 'time', 'for', 'a', 'few', 'good', 'ones', 'to', 'come', 'to', 'the', 'aid', 'of', 'new', 'things', 'to', 'come', 'for', 'it', 'is', 'almost', 'time', 'for', 'a', 'tornado', 'to', 'strike', 'upon', 'a', 'small', 'hill', 'when', 'least', 'expected']]
Tokens found [['NOW;', 'is', 'the', 'time', 'for', 'a', 'few', 'good', 'ones', 'to', 'come', 'to', 'the', 'aid', 'of', 'new', 'things', 'to', 'come', 'for', 'it', 'is', 'almost', 'time', 'for', 'a', 'tornado', 'to', 'strike', 'upon', 'a', 'small', 'hill', 'when', 'least', 'expected']]
ENDING Test 1
STARTING Test 2
Input Text is NOW; is the time for a few good ones to come to the aid
of new things to come for it is almost time for
a tornado to strike upon a small hill
when least expected.
lastly; another day progresses and
then we find that which we seek
and finally we will
find our happiness perhaps its closer than 1 or 2 years or not so
Grammar is {Group:({Combine:({W:(abcd...) ";"}) SkipTo:(~{Combine:({W:(abcd...) ";"})})})}...
Match Combine:({W:(abcd...) ";"}) at loc 0(1,1)
Matched Combine:({W:(abcd...) ";"}) -> ['NOW;']
Match SkipTo:(~{Combine:({W:(abcd...) ";"})}) at loc 4(1,5)
Match Combine:({W:(abcd...) ";"}) at loc 4(1,5)
Exception raised:Expected ";" (at char 7), (line:1, col:8)
Matched SkipTo:(~{Combine:({W:(abcd...) ";"})}) -> ['']
Match Combine:({W:(abcd...) ";"}) at loc 5(1,6)
Exception raised:Expected ";" (at char 7), (line:1, col:8)
After parse string: [['NOW;', '']]
Tokens found [['NOW;', '']]
ENDING Test 2
Process finished with exit code 0