On Feb 19, 2012, at 7:24 PM, Tom Lane wrote: > Don Baccus <dhog...@pacifier.com> writes: >> On Feb 19, 2012, at 5:42 PM, Tom Lane wrote: >>> Hmm, "pure" doesn't sound bad to me. Nice and short. > >> Technically, "pure" is stronger than "has no side effects": >> http://en.wikipedia.org/wiki/Pure_function >> Result can't depend on state (for instance, database contents), either. >> This is the typical definition used in functional programming. > > Well, that condition is subsumed in our idea of an immutable function.
Yes, I said that myself, perhaps you didn't bother to read closely? > It's not clear to me whether pure/leakproof functions are meant to be a > strict subset of immutable functions Superset, not subset, unless my guessing is wrong. How could "pure" be a subset of "immutable"? OK, at this point, proponents will explain why ... But if you're not clear as to what a "leakproof" function is meant to be. then I suggest the definition must be defined very clearly, so everyone understands what it is meant to be. > , but if they are then they meet > this stricter definition. On the other hand, if pure/leakproof functions > don't have to be immutable but only stable, then the stricter definition > corresponds to "pure immutable". That still doesn't sound too bad, as > long as we define our terms clearly in the docs. Sure, let those making the proposal make things clear. Just speaking as a gadfly who's not posted here for probably close on 10 years … ---- Don Baccus http://donb.photo.net http://birdnotes.net http://openacs.org -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
