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Re: CREATE OPERATOR and precedence

From: Marc Cousin <cousinmarc(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-docs(at)postgresql(dot)org
Subject: Re: CREATE OPERATOR and precedence
Date: 2010-07-08 15:42:22
Message-ID: 201007081742.22830.cousinmarc@gmail.com (view raw or flat)
Thread:
Lists: pgsql-docs
The Thursday 08 July 2010 16:31:41, Tom Lane wrote :
> Marc Cousin <cousinmarc(at)gmail(dot)com> writes:
> > I just got caught by a precedence problem with CREATE OPERATOR.
> > 
> > Obviously, it was mostly my fault (I didn't think of the precedence of my
> > operator at all), but I didn't find anything in the CREATE OPERATOR
> > documentation about it either.
> 
> CREATE OPERATOR has nothing to say on the subject because operator
> precedences are hard-wired into the parser and can't be changed by
> CREATE OPERATOR.  See
> 
> http://www.postgresql.org/docs/8.4/static/sql-syntax-lexical.html#SQL-PRECE
> DENCE
> 
> 			regards, tom lane

Yes, that's what I found out, afterwards.

From a technical point of view, I obviously totally agree, operators have no 
control over precedence, but I was only reporting this because I thought that 
it might be helpful to put something like a pointer to this table in the 
CREATE OPERATOR doc.

From the user's point of view, even if precedence is hard-wired in the parser, 
a note about it could help here, if only as a reminder. The first thing I 
thought when facing the problem was : "how do I specify the precedence ?". I 
found out I couldn't, but a pointer or a note would have been even easier.


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Subject: Re: CREATE OPERATOR and precedence
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