pyparsing.py 文件源码

def setParseAction( self, *fns, **kwargs ):
        """
        Define one or more actions to perform when successfully matching parse element definition.
        Parse action fn is a callable method with 0-3 arguments, called as C{fn(s,loc,toks)},
        C{fn(loc,toks)}, C{fn(toks)}, or just C{fn()}, where:
         - s   = the original string being parsed (see note below)
         - loc = the location of the matching substring
         - toks = a list of the matched tokens, packaged as a C{L{ParseResults}} object
        If the functions in fns modify the tokens, they can return them as the return
        value from fn, and the modified list of tokens will replace the original.
        Otherwise, fn does not need to return any value.

        Optional keyword arguments:
         - callDuringTry = (default=C{False}) indicate if parse action should be run during lookaheads and alternate testing

        Note: the default parsing behavior is to expand tabs in the input string
        before starting the parsing process.  See L{I{parseString}<parseString>} for more information
        on parsing strings containing C{<TAB>}s, and suggested methods to maintain a
        consistent view of the parsed string, the parse location, and line and column
        positions within the parsed string.

        Example::
            integer = Word(nums)
            date_str = integer + '/' + integer + '/' + integer

            date_str.parseString("1999/12/31")  # -> ['1999', '/', '12', '/', '31']

            # use parse action to convert to ints at parse time
            integer = Word(nums).setParseAction(lambda toks: int(toks[0]))
            date_str = integer + '/' + integer + '/' + integer

            # note that integer fields are now ints, not strings
            date_str.parseString("1999/12/31")  # -> [1999, '/', 12, '/', 31]
        """
        self.parseAction = list(map(_trim_arity, list(fns)))
        self.callDuringTry = kwargs.get("callDuringTry", False)
        return self