Access current state

So I have a virtual thermostat. The set-point varies based on mode/time of day. How can another rule access what the current set-point state is?

It depends on where you want to "access" this value (and which exact attribute you're looking for ... coolingSetpoint, maybe? there's also thermostatSetpoint that reports either the heating or cooling setpoint in accordance with the thermostat's current thermostatMode, at least in any device I've used).

If in a trigger, you could use "Thermostat cool setpoint." If in a conditional in an action, you could use "Thermostat cool setpoint" there as well. If you're doing something else, you might need to create a local (or global) variable of type "Number" and assign the value of this attribute to that variable (use "device attribute" when setting it, then choose this device and the desired attribute, coolingSetpoint if my guess is correct); then you could use that variable in other actions or do math on it as needed. These would all be things you could do from the "other" rule (since there was no mention of any existing rule, I'm assuming you might have one already that manipulates this thermostat and are thinking of adding a second that uses these values somehow?).

If this doesn't make sense, it might be best to provide an example of how/where you want to use this attribute's value. Otherwise, hopefully this helps!