## sloop

Before we go on I want to introduce the sloop package:

library(sloop)

The sloop package (think “sail the seas of OOP”) provides a number of helpers that fill in missing pieces in base R. The first of these is sloop::otype(). It makes it easy to figure out the OOP system used by a wild-caught object:

otype(1:10)
#> [1] "base"

otype(mtcars)
#> [1] "S3"

mle_obj <- stats4::mle(function(x = 1) (x - 2) ^ 2)
otype(mle_obj)
#> [1] "S4"

Use this function to figure out which chapter to read to understand how to work with an existing object.