pairlist.ok argument in assertList()

[tdeenes]

assertList(x) throws an error if x is a pairlist object. From the base-R point of view, this is unexpected:

# create a pairlist
p <- pairlist(x = 1)
class(p)
# p is a list according to base R
base::is.list(p)
# p is not a list according to checkmate
checkmate::testList(p)

One might argue that a pairlist is a special list which should not be considered as a list by default, but in this case this should be documented in ?assertList.

Note that this is not an issue of unevaluated symbols in a list:

a <- alist(x = not_existing_variable)
testList(a)

An easy workaround would be to introduce a new argument to checkList: pairlist.ok = FALSE so that it does not affect existing code. Later the default could be changed to TRUE.

[mllg]

You are totally right. I have documented this behavior until I find some time to fix this (pairlists are strangely implemented in C).