Light Sensor Programming Help

Just a quick (hopefully quick) question on light sensors. Is there any way I would be able to make it so if the light sensor saw dark then light, it would move to the left? And would you be able to use a light sensor in place of a line follower?

To answer your first question, yes you can make your robot move towards darkness using a light sensor. Take a look at this thread here. This kid is trying to do something similar but more or less the opposite of what you want to do. He is moving towards the light instead of away from it. This Thread.
As far as using it in place of a line following sensor it is possible but I don’t know how well it would work. You would have to try it out.