[Rd] Discrepancy between is.list() and is(x, "list")

[Abs Spurdle]

> the prison made by ancient design choices

That prison of ancient design choices isn't so bad.

I have no further comments on object oriented semantics.
However, I'm planning to follow the following design pattern.

If I set the class of an object, I will append the new class to the
existing class.

#good
class (object) = c ("something", class (object) )

#bad
class (object) = "something"

I encourage others to do the same.