On Tue, Dec 22, 2015 at 2:28 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Uriy Zhuravlev <u.zhurav...@postgrespro.ru> writes: >>> I'm dubious that the parsetree representation is well-chosen. >>> Probably a single is_slice flag would have been better. > >> What do you mean? This flag is for what? You are about the A_Indices >> node(lidx_default/uidx_default)? > > Yes. Those flags are partially redundant with the subtree pointers being > NULL, and there are combinations that would be invalid (such as > lidx_default being set but lidx not being null), and it's pretty unobvious > what the difference in representation is between a non-slice case and a > slice case with only the upper index provided. In fact, since you have > five syntaxes to represent, it's impossible for the two bools to > distinguish them all, which means that at least one case *must* be > identified by null-ness of a pointer contradicting what the corresponding > bool's setting would imply. So this just seems like a mess to me. > > I think it would come out cleaner if you had just one bool is_slice, > which corresponds directly to whether a colon was present. The four > sub-possibilities of colon notation would be represented by combinations > of null and non-null lidx and uidx. With is_slice false, the only valid > case is lidx==NULL, uidx!=NULL, as before for non-slice notation.
Patch is still in the works and author is still active, so moved to next CF. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
