Re: pl/pgsql: END verbosity

On 6/22/2005 1:29 AM, Neil Conway wrote:

> Tom Lane wrote:
>> The long-term point in my mind is that removing syntactical
>> redundancy always reduces the ability to detect errors or report
>> errors acccurately
>
> Lexical scoping is unambiguous in a language like PL/PgSQL. Since it is
> simple to determine whether a given END matches an IF, LOOP, or BEGIN, I
> don't see how it would reduce our "ability to detect errors or report
> errors accurately".
>
>> Consider for example the possibility that Oracle's next release adds
>> some new frammish that can't be duplicated because we chose not to
>> distinguish various forms of "END xxx" ...
>
> As lexical scoping is still unambiguous, we could actually add a K_LOOP
> / K_IF token to the input stream, if that would make you happier :) (Of
> course I'm not suggesting this -- the point is that as far as the parser
> is concerned, we should have precisely the same information for
> disambiguating the input as we used to have.)
>
> BTW, I notice that Oracle actually allows:
>
> <<label>>
> LOOP
> -- ...
> END LOOP label;

But what if they decide to allow

LOOP
-- ...
IF condition THEN
EXIT;
END LOOP;

at some point? There you'd get ambiguity.

Jan

>
> whereas we don't allow the optional label following END LOOP. Which goes
> to my general point: this frammish has existed in PL/SQL for a while,
> but it's not as if people are clamoring for us to implement it. I would
> wager that most people care about having *equivalent* features to
> PL/SQL, not exactly identical syntax. For example, the lack of
> autonomous transactions is something people have asked for in the past,
> because it *does* make porting PL/SQL applications more difficult. I
> can't see anyone losing any sleep because we are slightly more relaxed
> about the input we accept.
>
> -Neil
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
> http://archives.postgresql.org

--
#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me. #
#================================================== JanWieck(at)Yahoo(dot)com #