Allow defining notebook values in the Notebook API

[altavir]

I would like to be able to define new global variables/values in the notebook both from library descriptors and the Notebook reflection API.

My current use case is the following: I want to be able to change the properties of the plotly server from inside the notebook. For example, I would like to start it, stop it, and change the port. Ideal way is to write something like this:

%use plotly-server

plotlyServer.stop()
plotlyServer.port  = 22
plotlyServer.start()

In order to do that In should be able to define new properties through the notebook API like fun Builder.define(map: Map<String, Any>) or defineVariable(map: Map<String, Any>).

Current workaround suggested by @ileasile is to define empty variable via script execution:

val conf = execute("val libConf = LibConf(...); libConf").value as LibConf

and then substitute the value via

onVariable<LibConf> { value, prop ->
    prop as KMutableProperty<*>
    // prop.set(..)
}