Another interesting item ... I see that you added a collation field to TypeName, apparently on the grounds that the SQL spec includes collation in <data type>. However, it seems to me that that is nonsense up with which we should not put. <data type> is basically only used in CAST and column definitions (plus some features related to methods, which we haven't got). In CAST, they have to have a syntax rule stating that you must not use COLLATE in the target type name. In column definitions, they call out <collate clause> as a separate syntactic element, and then they have to have a syntax rule stating that you can't use both that and a <collate clause> embedded in the type name. This is just stupid. And it conflates the notion of collation with that of type --- based on our discussions so far, it seems like it'd be a lot better to keep those separate.
I think we should drop <collate clause> from TypeName and just have it in columnDef and the expression syntax. This might also ease the ambiguity problem that evidently led you to restrict the expression production's argument to c_expr. It would also allow us to meet the letter of the spec for <column definition>, in that <collate clause> is not required to immediately follow <data type>. I see that right now you don't allow <collate clause> in ColQualList, so it's not accepting syntax that the spec says is valid; and you really can't fix that as long as <collate clause> can be part of TypeName, because then there would be two ways to parse the case where COLLATE does immediately follow the type name. Thoughts? regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers