Pyparsing SetParseAction 问题
我是 pyparsing 的新手，我正在尝试使用 setParseAction 但有时不会被调用。 代码。
def fun():
comdty_tok = StringStart() + Word(alphas) + StringEnd()
comdty_tok.setParseAction(call_back)
comdty_tok.leaveWhitespace()
return comdty_tok
def call_back(p):
print 'Calling ....'
print p
class ComdtyTok(Token):
comdty_tok = StringStart() + Word(alphas) + StringEnd()
comdty_tok.setParseAction(call_back)
comdty_tok.leaveWhitespace()
parseImpl = comdty_tok.parseImpl
class SymParser(object):
tok = ComdtyTok()
@staticmethod
def parse(symbol):
p = SymParser.tok.parseString(symbol)
print p
print "Second"
x = fun()
x.parseString(symbol)
return p
SymParser.parse('ABCD')
这是我不明白为什么第一次不调用 setParseAction 的
I am a new-bee to pyparsing I am trying to experiment with setParseAction but it is not being called sometimes.
Here is the code
def fun():
comdty_tok = StringStart() + Word(alphas) + StringEnd()
comdty_tok.setParseAction(call_back)
comdty_tok.leaveWhitespace()
return comdty_tok
def call_back(p):
print 'Calling ....'
print p
class ComdtyTok(Token):
comdty_tok = StringStart() + Word(alphas) + StringEnd()
comdty_tok.setParseAction(call_back)
comdty_tok.leaveWhitespace()
parseImpl = comdty_tok.parseImpl
class SymParser(object):
tok = ComdtyTok()
@staticmethod
def parse(symbol):
p = SymParser.tok.parseString(symbol)
print p
print "Second"
x = fun()
x.parseString(symbol)
return p
SymParser.parse('ABCD')
I dont understand why the setParseAction is not called for the first time.
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我刚刚第一次使用 pyparsing，所以......
在初始化类变量 comdty_tok 时，您从未真正调用过 parseString() ，因此与解析对象关联的回调从未被调用过。
I just played with pyparsing for the first time, so ...
In initializing the class variable
comdty_tokyou never actually callparseString(), therefore the callback associated with the parse object is never called.我只能说，我并不是真的打算像您所做的那样扩展像 Token 这样的类。我怀疑在您对包含的
cmdty_tok属性的委托中，您忽略了公开一些其他属性，例如parseAction，该属性通常会在解析时由引用parseImpl。另一方面，您的 fun() 实现与我使用过和见过的其他帮助器和闭包非常一致，毫不奇怪，这种方法有效。您想通过
ComdtyTok实现什么目标？All I can say is that I did not really intend for classes like Token to be extended in the manner that you have done. I suspect that in your delegation to the contained
cmdty_tokattribute that you have omitted exposing some other attribute, such asparseAction, which would normally be referenced at parse time byparseImpl. On the other hand, your implementation offun()is very consistent with other helpers and closures I have used and seen used, and not surprisingly, this approach works.What are you trying to accomplish with
ComdtyTok?