Huh? I didn't say programs in other languages ship with bugs. But the bugs that
did have to be fixed include many that stem from NPEs.
Similarly, type safety in general helps keeps you safe from type mismatch bugs.
-------------------------------------
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.
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.
For more options, visit this group at
http://groups.google.com/group/liftweb?hl=.
--
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=.
