Vaggelis Papoutsis authored May 18, 2022 and Andrew Heather committed Jun 10, 2022

in RASModelVariables were doing this by checking whether the
corresponding pointer was allocated. In some cases, however, even if the
field does not exist, the pointer is not null, leading to the wrong
output. Made the correspding functions virtual and overwritten their
return values in the derived classes. Kept the initial implementation in
base to facilitate the clone function.