[HACKERS] IS OF

[Joe Conway]

While messing around in gram.y I came across a production like this:

| a_expr IS OF '(' type_list ')' %prec IS
{
  $$ = (Node *) makeSimpleA_Expr(AEXPR_OF, "=", $1, (Node *) $5);
}
| a_expr IS NOT OF '(' type_list ')' %prec IS
{
  $$ = (Node *) makeSimpleA_Expr(AEXPR_OF, "!=", $1, (Node *) $6);
}
Works like so:

regression=# select array[1,1.2] is of (numeric[]);
 ?column?
----------
 t
(1 row)
Pretty handy! But I couldn't find it documented anywhere -- is it?

Thanks,

Joe

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