Re: [HACKERS] GSoC 2017: Foreign Key Arrays - Mailing list pgsql-hackers

select '1'::text <<@ ARRAY[1::integer,2::integer];

ERROR:  operator does not exist: text <<@ integer[]

LINE 1: select '1'::text <<@ ARRAY[1::integer,2::integer];

HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.

select 1::integer <<@ ARRAY['1'::text,'2'::text];

ERROR:  operator does not exist: integer <<@ text[]

LINE 1: select 1::integer <<@ ARRAY['1'::text,'2'::text];

HINT:  No operator matches the given name and argument types. You might need to add explicit type casts.

doc/src/sgml/indices.sgml
-&lt;@ &nbsp; @&gt; &nbsp; = &nbsp; &amp;&amp;
+&lt;@ @&gt; &nbsp; &lt;&lt;@ @&gt;&gt; &nbsp; = &nbsp; &amp;&amp;
* To me it looks like the pattern is to insert &nbsp; between each operator

src/backend/access/gin/ginarrayproc.c
        /* Make copy of array input to ensure it doesn't disappear while in use */
-       ArrayType  *array = PG_GETARG_ARRAYTYPE_P_COPY(0);
+       ArrayType  *array;
I think the comment above should be changed/moved

src/backend/utils/adt/arrayfuncs.c
+               /*
+                * We assume that the comparison operator is strict, so a NULL can't
+                * match anything.  XXX this diverges from the "NULL=NULL" behavior of
+                * array_eq, should we act like that?
+                */
It seems unnecessary to have this open question.

array_contains_elem(AnyArrayType *array, Datum elem,
+       /*
+        * Apply the comparison operator to each pair of array elements.
+        */
This comment has been copy/pasted from array_contain_compare().
Maybe the wording should clarify there is only one array in this function,
the word "pair" seems to imply working with two arrays.

+       for (i = 0; i < nelems; i++)
+       {
+               Datum elt1;
The name `elt1` originates from the array_contain_compare() function.
But since this function, array_contains_elem(), doesn't have a `elt2`,
it would be better to use `elt` as a name here. The same goes for `it1`.