[HACKERS] [Q] When should I use reg* types instead of oid in the system catalog?

Hello,


Both pg_aggregate.aggfnoid and pg_trigger.tgfoid references
pg_proc.oid, but the data types of them are regproc and oid
respectively.  Is there any criterion on when to which in the system
catalog?  Is the regproc choice just for readability of the catalog
query output?  Should pg_trigger.tgfoid also have been changed to
regproc?

Regards
MauMau