Send data from a inner CG variable back to a Shaderlab property, is it possible?

I know that you can get data from a Shaderlab property to a CG inner program, is there a way to get a variable value back to a Shaderlab property from the inner CG program?

The short answer is no, the long answer is yes but only if you are able to write the data to a texture and then read the texture in a script, which can be a slow process and quite often negates the purpose of the shader in the first place.