Yes, if by nested you mean: a is true and (b is true or c is true) The statement in parenthesis gets evaluated first.
Bob On Oct 5, 2011, at 2:20 PM, Pete wrote: > Thanks, that's good to know. I'm looking at using a pretty complex > condition with some of the conditions being trivial but others taking up > significant database access so sounds like I should leave the db access > conditions until last. > > Hmmm, now I wonder if nested if statements make any difference to this. > Probably not. > > > Pete > Molly's Revenge <http://www.mollysrevenge.com> > > > > > On Wed, Oct 5, 2011 at 1:46 PM, Richard Gaskin > <ambassa...@fourthworld.com>wrote: > >> Pete wrote: >> >> I'm wondering how LC evaluates If statements with multiple conditions. >>> Are >>> all conditions evaluated before the overall result is checked for true or >>> false, or does evaluation proceed left to right and stop as soon as a >>> condition is found to be false? Whichever method is used, is it affected >>> by >>> some conditions being enclosed in parens? >>> >> >> IIRC from discussions with Dr. Raney many years ago, at some point he >> implemented an optimization in which the first part of any multi-condition >> expression that satisfies the expression avoids the need for evaluation of >> other conditions. This normally follows in left-to-right order, but of >> course using parens can alter the evaluation order. >> >> So in this conditional expression: >> >> if the short name of this cd is "Pete" and $user <> "pete" then >> >> If the short name of the card <> "Pete" then the engine wouldn't bother >> evaluating $user. >> >> -- >> Richard Gaskin >> Fourth World >> LiveCode training and consulting: http://www.fourthworld.com >> Webzine for LiveCode developers: http://www.LiveCodeJournal.com >> LiveCode Journal blog: >> http://LiveCodejournal.com/**blog.irv<http://LiveCodejournal.com/blog.irv> >> >> ______________________________**_________________ >> use-livecode mailing list >> use-livecode@lists.runrev.com >> Please visit this url to subscribe, unsubscribe and manage your >> subscription preferences: >> http://lists.runrev.com/**mailman/listinfo/use-livecode<http://lists.runrev.com/mailman/listinfo/use-livecode> >> >> > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your subscription > preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
