From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | "Colin 't Hart" <colinthart(at)gmail(dot)com>, Andrew Dunstan <andrew(at)dunslane(dot)net>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: What happened to the is_<type> family of functions proposal? |
Date: | 2010-09-21 15:49:56 |
Message-ID: | 3790.1285084196@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> I think it would be useful to have a way of testing whether a cast to
> a given type will succeed. The biggest problem with the
> exception-catching method is not that it requires writing a function
> (which, IMHO, is no big deal) but that exception handling is pretty
> slow and inefficient. You end up doing things like... write a regexp
> to see whether the data is in approximately the right format and then
> if it is try the cast inside an exception block. Yuck.
The problem here is that putting the exception handling in C doesn't
make things any better: it's still slow and inefficient. And in the
general case the only way to be sure that a string will be accepted by
the input function is to try it.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Robert Haas | 2010-09-21 15:56:51 | Re: What happened to the is_<type> family of functions proposal? |
Previous Message | Kevin Grittner | 2010-09-21 15:48:48 | Re: Do we need a ShmList implementation? |