| anySpecial | Detect whether there are any 'specials' in a formula term |
| expandGrpVar | apply |
| findReTrmClasses | list of specials - taken from enum.R |
| mkReTrms | Create list of structures needed for models with random effects |
| nobars | Omit terms separated by vertical bars in a formula |
| no_specials | Drop 'specials' from a formula |
| RHSForm | extract right-hand side of a formula |
| subbars | "Substitute bars" |