python - 如何不返回调用函数？

Question

在python中，如果在被调用函数中发生了某个事件，则有一种不返回到调用者函数的方法。例如，...

def acquire_image(sdkobject):

    ret = sdkobject.PrepareAcquisition()
    error_check(ret)

    ret = sdkobject.StartAcquisition()
    error_check(ret)

error_check是一个用于检查返回代码以查看sdk调用是否有错误的函数。如果这是一条错误消息，那么我不希望返回并获取图像，而是转到另一个函数以重新初始化sdk并从头开始。有pythonic的方法吗？

Answer 1

如果存在问题，请让error_check函数引发异常(例如SDKError)，然后在while循环中运行所有命令。

class SDKError(Exception):
    pass

# Perhaps define a separate exception for each possible
# error code, and make a dict that maps error codes to the
# appropriate exception.

class SDKType1Error(SDKError):
    pass

class SDKType5Error(SDKError):
    pass

sdk_errors = {
    1: SDKType1Error,
    5: SDKType5Error,
}

# Either return, if there was no error, or raise
# the appropriate exception
def error_check(return_code):
    if return_code == 0:
        return   # No error
    else:
        raise sdk_errors[return_code]


# Example of how to deal with specific SDKErrors subclasses, or a generic
# catch-all SDKError
def acquire_image(sdkobject):

    while True:
        try:
            # initialize sdk here
            error_check(sdkobject.PrepareAcquisition())    
            error_check(sdkobject.StartAcquisition())
        except SDKType1Error:
            # Special handling for this error
        except SDKError:
            pass
        else:
            break