Re: Precedence of new phrase search tsquery operator

On Wed, Jun 8, 2016 at 7:13 PM, Tom Lane <tgl@sss.pgh.pa.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