On Tue, Apr 9, 2024 at 11:37 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > Alexander Korotkov <aekorot...@gmail.com> writes: > > On Tue, Apr 9, 2024 at 5:12 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > >> * OrClauseGroupKey is not a Node type, so why does it have > >> a NodeTag? I wonder what value will appear in that field, > >> and what will happen if the struct is passed to any code > >> that expects real Nodes. > > > I used that to put both not-subject-of-transform nodes together with > > hash entries into the same list. This is used to save the order of > > clauses. I think this is an important property, and I have already > > expressed it in [1]. > > What exactly is the point of having a NodeTag in the struct though? > If you don't need it to be a valid Node, that seems pointless and > confusing. We certainly have plenty of other lists that contain > plain structs without tags, so I don't buy that the List > infrastructure is making you do that.
This code mixes Expr's and hash entries in the single list. The point of having a NodeTag in the struct is the ability to distinguish them later. ------ Regards, Alexander Korotkov
