Extend constructive — templates • constructive

.cstr_new_class() and .cstr_new_constructor() open new unsaved scripts, optionally commented, that can be used as templates to define new constructors. If the class is already supported and you want to implement a new constructor, use .cstr_new_constructor(), otherwise use .cstr_new_class().

Usage

.cstr_new_class(
  class = c("CLASS", "PARENT_CLASS"),
  constructor = "PKG::CONSTRUCTOR",
  commented = FALSE
)

.cstr_new_constructor(
  class = c("CLASS", "PARENT_CLASS"),
  constructor = "PKG::CONSTRUCTOR",
  commented = FALSE
)

Arguments

class: Class to support, provide the full class() vector.
constructor: Name of the constructor, usually the name of the function you can to use to build the object. If not you might need to adjust the script.
commented: Boolean. Whether to include comments in the template.

Value

Both function return NULL invisibly and are called for side effects

Details

We suggest the following workflow (summarized in a message when you call the functions):

Call usethis::use_package(\"constructive\", \"Suggests\")` one time at any point, this will add a soft dependency on 'constructive' so it's only needed to install it when you use it.
Call .cstr_new_class() or .cstr_new_constructor(), with commented = TRUE for more guidance.
Save the scripts unchanged in the "R" folder of your package.
devtools::document(): this will register the S3 methods.
Try construct() on your new object, it should print a call to your chosen constructor.
Tweak the code, in particular the definition of args.

The README of the example extension package 'constructive.example' guides you through the process. See also {constructive}'s own code and vignette("extend-constructive") for more details.