A refuting piece of evidence from the guy who created nulls. How cool is that?! :)
On Tue, Nov 17, 2009 at 1:20 AM, David Pollak <feeder.of.the.be...@gmail.com > wrote: > > > On Mon, Nov 16, 2009 at 9:01 PM, DMB <combust...@gmail.com> wrote: > >> >> that it's not null--which is a source of many bugs >> >> After a bold statement like this, one can't help but wonder how >> programmers manage to ship software in all the other languages. :-) >> Come to think of it, after working on a couple of pretty large ASP.NET >> projects (~50 devs), I haven't once seen a bug which was caused by the >> semantics of retrieving the cookie or URL parameter values. I'm not >> saying the Box thing doesn't have its uses, I'm just saying that in >> this particular case it's a pain in the ass and overkill. >> > > Before judging, spend a month or two writing idomatic Scala code rather > than fighting with it. > > In your example, I reduced the lines of code, made your code more logical > and reduced the McCabe complexity (see > http://en.wikipedia.org/wiki/Cyclomatic_complexity). The higher the > McCabe complexity, the more defects there are in software. > > So, even in a trivial 20 line program, using the Scala idioms shortens code > and generally makes code easier to read and easier to maintain. > > And we're not the only ones who think null is a problem... the guy that > invented null thinks it's a huge problem: > http://qconlondon.com/london-2009/presentation/Null+References:+The+Billion+Dollar+Mistake > > > >> >> On Nov 16, 2:40 pm, Naftoli Gugenheim <naftoli...@gmail.com> wrote: >> > As others may have said, the difference between a Box and a value that >> may be null is that both may or may not contain what you want it to have; >> but in one case the compiler lets you assume that it does--that it's not >> null--which is a source of many bugs. >> > Programming presents a tension between type safety and conciseness, and >> Scala does an amazing job of being extremely type safe and extremely >> concise. But type safety comes first. >> > >> > ------------------------------------- >> > >> > DMB<combust...@gmail.com> wrote: >> > >> > I guess that could work, but why go to such lengths where there are >> > much more straightforward solutions available? What do for >> > comprehensions buy you in this case? I mean, 99% of the time, when I >> > want to check for a cookie, I don't need the cookie itself or any of >> > its properties. I need its value, or null if there's no cookie. Why >> > not do something a-la RoR: >> > >> > S.cookieValue("cookieName") >> > >> > or a-la ASP.NET: >> > >> > val c = S.cookie("cookieName") >> > if(c != null) { >> > val v = c.value >> > >> > } >> > >> > Or, indeed, both? >> > >> > On Nov 16, 1:22 am, Sergey Andreev <andser...@gmail.com> wrote: >> > >> > > Hi, >> > >> > > For-comprehensions could help you out: >> > >> > > for{ >> > > cookie <- S.findCookie(cookieName) >> > > value <- cookie} doSomethingWithValue >> > >> > > Regards >> > >> > > On Mon, Nov 16, 2009 at 12:07 PM, DMB <combust...@gmail.com> wrote: >> > >> > > > When I call findCookie it returns a Box. Then, the value on the >> cookie >> > > > itself is also a box. Hence a ruby one-liner turns into something >> > > > like: >> > >> > > > val cookie = S.findCookie(cookieName) >> > > > if(cookie.isDefined) { >> > > > val cookieVal = cookie.open_!.value.openOr(null) >> > > > // Do something with the cookie value >> > > > } >> > >> > > > This is very ugly, so I'm guessing I'm doing something wrong, but >> try >> > > > as I might, I could not find any examples that would look even >> vaguely >> > > > "right" to me. >> > >> > > > Why can't findCookie return a simple, unboxed HTTPCookie object or >> > > > null if cookie is not found? >> > > > Why does the value inside a cookie need to also be Box'ed? >> > >> > > > For the sake of comparison, here's how you do the same thing in RoR: >> > > > v = cookies["cookieName"] >> > > > // Do something with the cookie >> > >> > > > or ASP.NET: >> > > > var c = Request.Cookies["CookieName"] >> > > > if(c != null) { >> > > > var v = c.Value >> > > > // Do something with the cookie >> > > > } >> > >> > > > I fail to see why Lift should be more complicated. >> > >> > > > This is with Lift 1.1 M7 >> >> -- >> >> You received this message because you are subscribed to the Google Groups >> "Lift" group. >> To post to this group, send email to lift...@googlegroups.com. >> To unsubscribe from this group, send email to >> liftweb+unsubscr...@googlegroups.com<liftweb%2bunsubscr...@googlegroups.com> >> . >> For more options, visit this group at >> http://groups.google.com/group/liftweb?hl=. >> >> >> > > > -- > Lift, the simply functional web framework http://liftweb.net > Beginning Scala http://www.apress.com/book/view/1430219890 > Follow me: http://twitter.com/dpp > Surf the harmonics > > -- > You received this message because you are subscribed to the Google Groups > "Lift" group. > > To post to this group, send email to lift...@googlegroups.com. > To unsubscribe from this group, send email to > liftweb+unsubscr...@googlegroups.com<liftweb%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/liftweb?hl=. > -- Jack Widman co-founder / cto, Authoritude, Inc. 203-641-9355 -- You received this message because you are subscribed to the Google Groups "Lift" group. To post to this group, send email to lift...@googlegroups.com. To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/liftweb?hl=.
