Re: CREATE OPERATOR and precedence
От | Marc Cousin |
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Тема | Re: CREATE OPERATOR and precedence |
Дата | |
Msg-id | 201007081742.22830.cousinmarc@gmail.com обсуждение исходный текст |
Ответ на | Re: CREATE OPERATOR and precedence (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: CREATE OPERATOR and precedence
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Список | 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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