On 02/26/2012 08:23 PM, Tom Lane wrote:
Robert Haas<robertmh...@gmail.com> writes:
On Sun, Feb 26, 2012 at 6:44 PM, A.M.<age...@themactionfaction.com> wrote:
http://en.wikipedia.org/wiki/Referential_transparency_(computer_science)
So a function could be described as "REFERENTIALLY TRANSPARENT".
Hmm, I think that's very close to what we're looking for. It might be
slightly stronger, in that it could conceivably be OK for a leakproof
function to read, but not modify, global variables... but I can't
think of any particular reason why we'd want to allow that case.
OTOH, it seems to imply that referential transparency is a property of
expressions built from pure functions, and since what we're labeling
here are functions, that brings us right back to PURE.
Yeah. Comparing that page to the one on pure functions, there doesn't
seem to be any difference that is relevant to what we're concerned
about. And neither page directly addresses the question of error
conditions, though if you hold your head at the proper angle you might
argue that that's implicit in the "no side effect" rule. But I think
we're going to have to clearly document that requirement no matter
what term we choose.
I'm thinking we should go with PURE.
Works for me.
Not for me. My objection is the same as when I started this thread -
that the term doesn't convey to someone just looking at it the salient
point about the feature, any more then LEAKPROOF does. SILENT strikes me
as much closer to what is actually described.
cheers
andrew
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
