pkg_resources.py 文件源码

def evaluate_marker(cls, text, extra=None):
        """
        Evaluate a PEP 426 environment marker on CPython 2.4+.
        Return a boolean indicating the marker result in this environment.
        Raise SyntaxError if marker is invalid.

        This implementation uses the 'parser' module, which is not implemented on
        Jython and has been superseded by the 'ast' module in Python 2.6 and
        later.
        """
        return cls.interpret(parser.expr(text).totuple(1)[1])