Earlier quoted context omitted.
A long time ago I settled on FST and RST as the Right Names for the two halves of a cons cell. The argument is: 1. It's vaguely mnemonic of FirST and ReST, but compactified enough that it's still parseable as abstract names with no particular semantics 2. It's composable the same way that CAR and CDR are, e.g. FFRST == CAADR. Another good pair of names is LHS and RHS for Left Hand Side and Right Hand Side. Same argum…
How do you define these so you can use them like CAADR?
Lather, rinse, repeat.
For extra credit, write a macro that will save you having to type every possible combination out manually.