Re: [HACKERS] Associative Operators? (Was: Re: [NOVICE] Out of frying pan, into fire)

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: clark(dot)evans(at)manhattanproject(dot)com (Clark Evans)
Cc: hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Associative Operators? (Was: Re: [NOVICE] Out of frying pan, into fire)
Date: 1999-03-16 22:23:52
Message-ID: 199903162223.RAA20888@candle.pha.pa.us
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> Seth McQuale pointed out that the follwing does not work:
> SELECT LASTNAME || ',' || FIRSTNAME [AS] NAME FROM FRIENDS;
>
> The solution, was:
> SELECT ( LASTNAME || ',' ) || FIRSTNAME AS NAME FROM FRIENDS;
>
> I looked at pg_operator and didn't see any flag to mark
> an operator as 'associative'. Perhaps if we added a flag
> like this, the re-write system could be modified to handle
> cases like this.
>
> Thoughts?
>
> Clark Evans
>
>

My guess is that we should auto-left-associate functions like || if no
parens are present. It would be a small change to the parser.

--
Bruce Momjian | http://www.op.net/~candle
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