目前,这是我“简化”的解析器的开头部分:
from pyparsing import *
bool_act = lambda t: bool(t[0])
int_act = lambda t: int(t[0])
def keyval_act(instring, loc, tokens):
return set([(tokens.k, tokens.v)])
def keyin_act(instring, loc, tokens):
return set([(tokens.k, set(tokens.vs))])
string = (
Word(alphas + '_', alphanums + '_')
| quotedString.setParseAction( removeQuotes )
)
boolean = (
CaselessLiteral('true')
| CaselessLiteral('false')
)
integer = Word(nums).setParseAction( int_act )
value = (
boolean.setParseAction(bool_act)
| integer
| string
)
keyval = (string('k') + Suppress('=') + value('v')
).setParseAction(keyval_act)
keyin = (
string('k') + Suppress(CaselessLiteral('in')) +
nestedExpr('{','}', content = delimitedList(value)('vs'))
).setParseAction(keyin_act)
grammar = keyin + stringEnd | keyval + stringEnd
"语法"非终结符目前仅是一个存根,我将最终向键中添加可嵌套的联结和析取,以便可以解析此类搜索:
a = 1, b = 2 , c in {1,2,3} | d = 4, ( e = 5 | e = 2, (f = 3, f = 4))
目前,我还不太明白pyparsing如何调用我的setParseAction函数。我知道在传递参数方面有一些魔法,但是我遇到了一个错误,即根本没有将任何参数传递给该函数。因此,如果我执行以下操作:
grammar.parseString('hi in {1,2,3}')
我遇到了这个错误:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.6/site-packages/pyparsing.py", line 1021, in parseString
loc, tokens = self._parse( instring, 0 )
File "/usr/lib/python2.6/site-packages/pyparsing.py", line 894, in _parseNoCache
loc,tokens = self.parseImpl( instring, preloc, doActions )
File "/usr/lib/python2.6/site-packages/pyparsing.py", line 2478, in parseImpl
ret = e._parse( instring, loc, doActions )
File "/usr/lib/python2.6/site-packages/pyparsing.py", line 894, in _parseNoCache
loc,tokens = self.parseImpl( instring, preloc, doActions )
File "/usr/lib/python2.6/site-packages/pyparsing.py", line 2351, in parseImpl
loc, resultlist = self.exprs[0]._parse( instring, loc, doActions, callPreParse=False )
File "/usr/lib/python2.6/site-packages/pyparsing.py", line 921, in _parseNoCache
tokens = fn( instring, tokensStart, retTokens )
File "/usr/lib/python2.6/site-packages/pyparsing.py", line 675, in wrapper
return func(*args[limit[0]:])
TypeError: keyin_act() takes exactly 3 arguments (0 given)
从回溯信息可以看出,我正在使用Python2.6和pyparsing 1.5.6。
有人能否给我一些见解,为什么该函数没有获得正确数量的参数?