Re: CREATE OPERATOR and precedence - Mailing list pgsql-docs

From Marc Cousin
Subject Re: CREATE OPERATOR and precedence
Date
Msg-id 201007081742.22830.cousinmarc@gmail.com
Whole thread Raw
In response to Re: CREATE OPERATOR and precedence  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: CREATE OPERATOR and precedence
List pgsql-docs
The Thursday 08 July 2010 16:31:41, Tom Lane wrote :
> Marc Cousin <cousinmarc@gmail.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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