Saver 不支持字符串变量吗？
Does Saver not support string variables?
内置检查点工具似乎不支持保存 string 变量？例如这失败了：
var = tf.Variable('hello world')
saver = tf.train.Saver()
如果是这样，有什么原因吗？
字符串支持已添加到（使用的操作）tf.train.Saver earlier this month, in this commit. This support is not available in the current (0.6.0) release, but it will appear in the next release. If you want to use it in the meantime, you should install TensorFlow from source。
内置检查点工具似乎不支持保存 string 变量？例如这失败了：
var = tf.Variable('hello world')
saver = tf.train.Saver()
如果是这样，有什么原因吗？
字符串支持已添加到（使用的操作）tf.train.Saver earlier this month, in this commit. This support is not available in the current (0.6.0) release, but it will appear in the next release. If you want to use it in the meantime, you should install TensorFlow from source。