When writing the generic range output function, it needs to know the
specific range type in order to call the subtype's output function.
Records accomplish this by using a special cache based on the typmod,
apparently, which looks like a hack to me.
Arrays accomplish this by storing the specific type in every array
value. That seems very wasteful in the case of range types (which only
hold two values).
I thought I could get away with using get_fn_expr_argtype() for most of
the generic functions, but apparently that can't always provide an
answer.
Any ideas? Maybe, with alignment and a "flags" byte (to hold
inclusivity, infinite boundaries, etc.), the extra 4 bytes doesn't cost
much, anyway?
Regards,
Jeff Davis