Re: Precedence of new phrase search tsquery operator

On Wed, Jun 8, 2016 at 7:13 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> It appears that the new <-> operator has been made to have exactly the
> same grammatical precedence as the existing & (AND) operator. Thus,
> for example, 'a & b <-> c'::tsquery means something different from
> 'b <-> c & a'::tsquery:
>
> regression=# select 'a & b <-> c'::tsquery;
> tsquery
> -----------------------------------
> ( 'a' <-> 'c' ) & ( 'b' <-> 'c' )
> (1 row)
>
> regression=# select 'b <-> c & a'::tsquery;
> tsquery
> -----------------------
> ( 'b' <-> 'c' ) & 'a'
> (1 row)
>
> I find this surprising. My intuitive feeling is that <-> ought to
> bind tighter than & (and therefore also tighter than |). What's
> the reasoning for making it act like this?

ah, now we remember :) The idea about equivalence of & and <->
operators appeared in situation when <-> degenerates to & in case of
absence of positional information. Looks like we mixed different
things, will fix.

>
> regards, tom lane