On Sun, Feb 26, 2012 at 6:44 PM, A.M. <age...@themactionfaction.com> wrote: > If you are willing to go full length, then the computer science term is > "referential transparency", no? > > 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. I'm thinking we should go with PURE. I still can't think of any real use case for pushing down anything other than an immutable function, and I think that immutable + no-side-effects = pure. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
