Re: factorial function/phase out postfix operators?

On Sat, Jul 11, 2020 at 1:14 AM Mark Dilger
<mark.dilger@enterprisedb.com> wrote:
>
> > Tom and Álvaro discussed upthread:
> >
> >> Would it make sense (and possible) to have a keyword category that is
> >> not disjoint wrt. the others?  Maybe that ends up being easier than
> >> a solution that ends up with six or seven categories.
>
> Version 2, attached, follows this design, increasing the number of keywords that can be used as column aliases without the AS keyword up to 411, with only 39 keywords still requiring an explicit preceding AS.

Hi Mark,

This isn't a full review, but I have a few questions/comments:

By making col-label-ness an orthogonal attribute, do we still need the
category of non_label_keyword? It seems not.

pg_get_keywords() should probably have a column to display ability to
act as a bare col label. Perhaps a boolean? If so, what do you think
of using true/false for the new field in kwlist.h as well?

In the bikeshedding department, it seems "implicit" was chosen because
it was distinct from "bare". I think "bare" as a descriptor should be
kept throughout for readability's sake. Maybe BareColLabel could be
"IDENT or bare_label_keyword" for example. Same for the $status var.

Likewise, it seems the actual removal of postfix operators should be a
separate patch.

-- 
John Naylor                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services