- proper-ilist? xprocedure
- ilist? xprocedure
These identifiers are bound either to the same procedure, or to procedures of equivalent behavior. In either case, true is returned iff x is a proper ilist — a ()-terminated ilist.
More carefully: The empty list is a proper ilist. An ipair whose icdr is a proper ilist is also a proper ilist. Everything else is a dotted ilist. This includes non-ipair, non-() values (e.g. symbols, numbers, mutable pairs), which are considered to be dotted ilists of length 0.