Ah, that's a good idea. Didn't think of that. Chas.
Jorge Ortiz wrote: > Also check out CanSpec.scala to get an idea of how Cans can be used. > > --j > > On Wed, Oct 15, 2008 at 9:33 AM, David Pollak <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> wrote: > > Charles, > > A Can is a container... it can contain a thing or be empty. > > You can transform the contents of a Can from one thing to another > using map(). map() on Can, Option, List is exactly the same as > map() on Array in Ruby: > irb(main):004:0> [1,2,3].map{|v| v.to_s + " Cats"} > => ["1 Cats", "2 Cats", "3 Cats"] > > This is just like in Scala: > scala> List(1,2,3).map(v => v.toString + " Cats") > res0: List[java.lang.String] = List(1 Cats, 2 Cats, 3 Cats) > > In Ruby, when you access the first element of an Array that has no > elements, you get 'nil' back. In Scala, you get an exception. This > allows you to tell the difference between [nil][0] and [][0] which > are the same in Ruby. > > The most syntactically pleasing way of extracting things from List, > Can, Option in Scala is the "for" comprehension: > > scala> for (a <- Some(3); > | b <- Some(4)) yield a * b > res1: Option[Int] = Some(12) > > > Does that help? > > Thanks, > > David > > > > > Charles F. Munat wrote: >> Thanks. I have read everything I could find on this but I think I'm just >> a bit dense about it. Probably, it's just unfamiliarity with the syntax >> of Scala as a whole and functional programming in general (or maybe I'm >> just stupid). Hopefully, at some point the light bulb will come on and >> this will seem easy. I'll read the blog post. >> >> Chas. >> >> David Pollak wrote: >> >>> Please also see: >>> >>> http://blog.lostlake.org/index.php?/archives/50-The-Scala-Option-class-and-how-lift-uses-it.html >>> >>> Can[T] is just like Option[T] >>> >>> Marius wrote: >>> >>>> to get stuff out of a can you can do: >>>> >>>> 1. Pattern matching >>>> >>>> having c a Can[String] >>>> >>>> c match { >>>> case Full(value) => //do something with the value >>>> case _ => >>>> } >>>> >>>> 2. call open_!(if you're sure your can is not empty) or openOr >>>> >>>> Br's, >>>> Marius >>>> >>>> On Oct 15, 3:22 am, "Charles F. Munat" <[EMAIL PROTECTED]> >>>> <mailto:[EMAIL PROTECTED]> wrote: >>>> >>>> >>>>> I must be very dense, but these cans are kicking my butt (kicking my >>>>> can?). No matter what I do, I seem to end up with everything back in >>>>> the >>>>> can! I just... want... to get... the goodies... OUT! >>>>> >>>>> An example: >>>>> >>>>> How do I extract the URI of the current page from S.request? >>>>> >>>>> I am currently doing something immensely stupid and wrong like this: >>>>> >>>>> >>>>> S.request.toList.head.location.toList.head.createDefaultLink.toList.head.text >>>>> >>>>> I *know* this is way wrong, but I'm not clever enough, apparently, to >>>>> figure out the puzzle, despite reading through the Can code >>>>> repeatedly. >>>>> I figure the above works only because what I'm looking for is there, >>>>> which sort of defeats the purpose of the cans... >>>>> >>>>> Can anyone help? This is driving me insane. >>>>> >>>>> Chas. >>>>> >>>>> >>>> >>>> >> > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Lift" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~----------~----~----~----~------~----~------~--~---
