This uses inc/dec if b is in the range of int32 (which avoids allocating a temporary BigInt), at the cost of an additonal range check. I chose to not change the type from int to int32, since succ/prec for Ordinals also take an int (we might want to make inc/dec take an int as well for the same reason). Although if you prefer taking an int32, I can happily change that.
This uses
inc/decifbis in the range ofint32(which avoids allocating a temporaryBigInt), at the cost of an additonal range check. I chose to not change the type frominttoint32, sincesucc/precforOrdinals also take anint(we might want to makeinc/dectake anintas well for the same reason). Although if you prefer taking anint32, I can happily change that.