Plotting output/input values

[kakila]

How one does plot the values of the input/output pins?
For example, from the RC circuit example (not working on v1.4.0 , see #70) one plots the current and voltage in the components with

plot(sol, vars = [capacitor.v,resistor.i])

but (as I was expecting being used to work with MTK) this doesn't work

plot(sol, vars = [capacitor.v, resistor.i, source.V])

or in the modified version (#70)

plot(sol, vars = [C.v, R.i, V.V])

or

plot(sol, vars = [C.v,R.i, source.output])

Is this because we are not composing the systems but directly assemble the ODESystem? or is it an effect of the connect function?

[baggepinnen]

You currently need to use source.output.u since source.output is a connector. I find this quite annoying and would be happy to figure out a solution such that simply typing source.output would work.

For this connector, there is only a single variable that could be plotted, but in general there may be any number of plottable variables in a connector. Maybe SciMLBase.solution_interface could introduce an access function plot_representation etc. that is called on each symbol that is passed in. The default implementation would simply be the identity

plot_representation(x) = x

but ODESystem could overload this to something like the following

plot_representation(sys::ODESystem) = length(states(sys)) == 1 ? states(sys)[] : error()