Interesting on the use of parens in this situation. I guess it makes sense it works the way it does but it doesn't really come across that way in the manual. Pete lcSQL Software <http://www.lcsql.com>
On Sun, Jan 27, 2013 at 10:53 AM, Mike Bonner <bonnm...@gmail.com> wrote: > ifs are evaluated left to right, though there is some leeway using parens. > > As to your question though, yes putting slower evals at the end of a string > of ands and ors does save time if the if fails before the slow parts. > > Did the following in a button to test. Just change one of the first > conditions to be false and the long myfunc call is never hit. Placed > parens around the myfunc() to demonstrate that they don't give precedence > in this situation. > > *on* mouseUp > > *if* 1 is 1 and 2 is 2 and (myfunc()) *then* *put* "It's all true" > > *end* mouseUp > > > *function* myFunc > > *repeat* 10000 times > > *put* random(10) > > *end* *repeat* > > *if* random(2) is 1 *then* > > *return* true > > *else* > > *return* false > > *end* *if* > > *end* myFunc > > > > On Sun, Jan 27, 2013 at 11:39 AM, Peter Haworth <p...@lcsql.com> wrote: > > > Musings about complex if statements on this Sunday morning.... > > > > Lets say you have a complex if statement with 4 conditions that must all > be > > true. Is there any advantage, other than personal preference/style, to: > > > > if cond1 and cond2 and cond3 and cond4 then..... > > > > or > > > > if cond1 then > > if cond2 then > > if cond3 then > > if cond4 then... > > > > In either case, as soon as a condition evaluates to false, none of the > rest > > are evaluated, right? If so, then always best to put the conditions that > > take the longest to evaluate further down the list, for example perhaps > an > > SQL SELECT statement that might take a while to execute? But then what > if > > some of the conditions are in parens, for example: > > > > if cond1 and cond2 and (cond3 and cond4) then.... > > > > The manual says the grouping operator (parens) has the highest precedence > > so does this mean (cond3 and cond4) will be evaluated before cond1 and > > cond2? > > > > Just curious. > > > > > > Pete > > lcSQL Software <http://www.lcsql.com> > > _______________________________________________ > > 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 > _______________________________________________ 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
