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rpackager-s4

In R, how can I reference an S4 class from another package in my class definition?

Suppose I have two packages PackageA and PackageB. I have an S4 class, ClassA, in PackageA that I would like to use as a base class for ClassB in PackageB: 

setClass(
    "ClassB", 
    slots = c(), 
    validity = function(object) {

        T
    }
    contains = "ClassA")

However, when I build I get the error:

no definition found for superclass "ClassA"

I have tried adding a reference to the PackageA with devtools: 

devtools::use_package("PackageA")

Perhaps I need to use an roxygen directive?

Solution

  • Turns out that ClassA was not being imported properly. Adding the correct roxygen directive solved the problem: 

    #' @import PackageA
setClass(
    "ClassB", 
    slots = c(), 
    validity = function(object) {

        T
    }
    contains = "ClassA")