[Rd] is class2 Parameter's Documentation is Ambiguous

[Dario Strbenac]

Good day,

It appears that class2 needs to be of length 1.

> is(4, c("data.frame", "DataFrame"))
Error in is(4, c("data.frame", "DataFrame")) : 
  length(class2) == 1L is not TRUE

However, the documentation is "class1, class2: character strings giving the names of each of the two classes between which is relations are to be examined"

Also, class1 is not a parameter of the is function. It is a parameter of the extends function. I think the mention of "is relations" is unintended. Can the documenation be rewritten to remove the ambiguity for these?

--------------------------------------
Dario Strbenac
University of Sydney
Camperdown NSW 2050
Australia