2010/11/18 Tom Lane <tgl@sss.pgh.pa.us>:
> Andrew Dunstan <andrew@dunslane.net> writes:
>> Syntactic sugar is not entirely to be despised, anyway.
>
> If it were harmless syntactic sugar I wouldn't be objecting so loudly.
> The problem here is that FOR is a syntactic choke point: it's already
> overloaded with several different sub-syntaxes that are quite difficult
> to separate. Adding another one makes that worse, with the consequences
> that we might misinterpret the user's intent, leading either to
> misleading/unhelpful error messages or unexpected runtime behavior.
> If you consult the archives you can find numerous past instances of
> complaints from people who hit such problems with the existing set of
> FOR sub-syntaxes, so this isn't hypothetical.
>
yes, this argument is correct - but we can rearange a parser rules
related to FOR statement. It can be solved.
> I'm also quite afraid of having a conflict with other future extensions
> of FOR, which we might want to introduce either on our own hook or for
> compatibility with something Oracle might add to PL/SQL in future.
we talked about it last time - and I respect it - syntax is FOR IN
>>>ARRAY<<< expression
>
> This might not be the worst place in the entire system to be introducing
> inessential syntactic sugar, but it's certainly one of the top ten.
> I would *much* rather we get the performance benefit by internal
> optimization, and forego inventing syntax.
>
Regards
Pavel
> regards, tom lane
>