In the model-class documentation, we can read :
"
[<-
model[i]<-value copies the contents of the value into the i-th basic structure of the model-class
"
When I try the following sequence
mdlt<-model.create(melem.name(2),ndim=2) #Creation of a first model
mdlt<-model.create(melem.name(3),ndim=2,model=mdlt) #Append a second model
value<-model.create(melem.name(4),ndim=2) #Creation of a third model
mdlt[1]<-value #use of the assignment operator
mdlt
R closes and with the following message
terminate called after throwing an instance of 'Rcpp::no_such_slot'
what(): no such slot