Readonlyargthe index of that argument when it is passed positionally
Readonlyargthe name of the argument holding the function
Readonlycallthe call taking the function, e.g. shiny::shinyApp
Readonlyparamswhich LinkedInputObject the framework binds to each parameter, by position; undefined leaves one alone
A call a framework is given a function through, binding its parameters by position - which is how R passes them, so this catches a
shinyApp(ui, function(i, o, s))that no name-based rule can.