Though I am not fond of these macros for our core code (it makes the
code more cumbersome especially for using private data in derivable
types), this definitely makes sense for public API, since it would allow
easier modifications with less chances of messing API/ABI stability.
The CLI options now know which procedures are batch procedures or not.
First it means that it won't just randomly try any procedure name one
may pass and will properly output an error if you pass a non-existing
interpreter procedure.
Secondly, there is no default interpreter anymore (unless only one
interpreter exists). If you don't set an interpreter procedure with
--batch-interpreter or if you pass a wrong one, it will output the list
of available batch procedure, thus helping you understanding how to use
the --batch option.