Re: factorial function/phase out postfix operators?

Pavel Stehule <pavel.stehule@gmail.com>

From: Pavel Stehule <pavel.stehule@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2020-05-19T12:33:38Z
Lists: pgsql-hackers
út 19. 5. 2020 v 14:27 odesílatel Robert Haas <robertmhaas@gmail.com>
napsal:

> On Mon, May 18, 2020 at 10:42 AM Peter Eisentraut
> <peter.eisentraut@2ndquadrant.com> wrote:
> > What are the thoughts about then marking the postfix operator deprecated
> > and eventually removing it?
>
> I wrote a little bit about this last year:
>
>
> http://postgr.es/m/CA+TgmoarLfSQcLCh7jx0737SZ28qwbuy+rUWT6rSHAO=B-6xdw@mail.gmail.com
>
> I think it's generally a good idea, though perhaps we should consider
> continuing to allow '!' as a postfix operator and just removing
> support for any other. That would probably allow us to have a very
> short deprecation period, since real-world use of user-defined postfix
> operators seems to be nil -- and it would also make this into a change
> that only affects the lexer and parser, which might make it simpler.
>
> I won't lose a lot of sleep if we decide to rip out '!' as well, but I
> don't think that continuing to support it would cost us much.
>

This is little bit obscure feature. It can be removed and relative quickly.
Maybe some warning if somebody use it can be good (for Postgres 13)

Pavel


> --
> Robert Haas
> EnterpriseDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
>
>
>

Commits

  1. Remove precedence hacks no longer needed without postfix operators.

  2. Allow most keywords to be used as column labels without requiring AS.

  3. Remove support for postfix (right-unary) operators.

  4. Remove factorial operators, leaving only the factorial() function.

  5. Further refine patch for commenting operator implementation functions.