Re: C function proposal redux

On Wed, 13 Dec 2000, mlw wrote:

> I propose we modify C functions for 7.2. 
Too simple imagine anything, but often difficult do it :-)

> (1) C functions should be able to return multiple values.
for 7.2 / 7.3 are planned functions return tuples, but do it 
is really diffucult. See the current source...

> (2) A setup and breakdown function should be able to be called
> surrounding the query set in which a function is called. This allows
> constructors and destructors.
Why? Can you show any example where is it needful? If you really
need an init/destroy, you can use:

SELECT my_init();
..query...
SELECT my_destroy();

> (3) A function should be able to tell Postgres how to use it. For
> instance:
> 
> select * from table where column = function();
> 
> Should be able to instruct Postgres to either take the value returned
> and search that one value (allowing index match against the value), or
> perform a table scan against the function each time. Both behaviors are
> important. Currently a function seems to force a table scan.

Here I not undestand. We have 'iscacheable' - or what you mean? 

            Karel