Model component concentration as an explicit function

[melkonyan]

Let's say component is a drug, I'd like to explicitly specify its concentration as a function of time, to do sth like "dosing" in matlab's simbiology. Is it currently possible?

[jmuhlich]

Not as part of the model itself, since we don't yet have a way to expose "time" as a variable for expressions to use. We have #534 to track work on this feature, and #533 is another request for this feature from an end user.