On Tue, Dec 22, 2015 at 11:51 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > I'm reviewing Yury Zhuravlev's patch to allow array slice boundaries to be > omitted, for example "a[4:]" means "the slice extending from element 4 to > the last element of a". It strikes me that there's an improvement we > could easily make for the case where a mixture of slice and non-slice > syntax appears, that is something like "a[3:4][5]". Now, this has always > meant a slice, and the way we've traditionally managed that is to treat > simple subscripts as being the range upper bound with a lower bound of 1; > that is, what this example means is exactly "a[3:4][1:5]". > > ISTM that if we'd had Yury's code in there from the beginning, what we > would define this as meaning is "a[3:4][:5]", ie the implied range runs > from whatever the array lower bound is up to the specified subscript. > > This would make no difference of course for the common case where the > array lower bound is 1, but it seems a lot less arbitrary when it isn't. > So I think we should strongly consider changing it to mean that, even > though it would be non-backwards-compatible in such cases. > > Comments?
Gosh, our arrays are strange. I would have expected a[3:4][5] to mean a[3:4][5:5].