pyparsing.py 文件源码

def _ustr(obj):
        """Drop-in replacement for str(obj) that tries to be Unicode friendly. It first tries
           str(obj). If that fails with a UnicodeEncodeError, then it tries unicode(obj). It
           then < returns the unicode object | encodes it with the default encoding | ... >.
        """
        if isinstance(obj,unicode):
            return obj

        try:
            # If this works, then _ustr(obj) has the same behaviour as str(obj), so
            # it won't break any existing code.
            return str(obj)

        except UnicodeEncodeError:
            # Else encode it
            ret = unicode(obj).encode(sys.getdefaultencoding(), 'xmlcharrefreplace')
            xmlcharref = Regex(r'&#\d+;')
            xmlcharref.setParseAction(lambda t: '\\u' + hex(int(t[0][2:-1]))[2:])
            return xmlcharref.transformString(ret)

    # build list of single arg builtins, tolerant of Python version, that can be used as parse actions