Greg, This sounds interesting... but I'd like to see what the Scala code would look like that would manipulate the Zipper-based data structures. If you've got a pile of XML, what does it look like to map it to nested [case] classes? What does it look like to manipulate the XML?
Thanks, David On Fri, Jul 17, 2009 at 10:54 AM, Meredith Gregory <lgreg.mered...@gmail.com > wrote: > Guys, > > After playing around with integrating Lift and Jersey before the Jersey > guys did an 'official' integration and thinking hard about how i wanted to > reference locations in data structures via URLs, i realized that > zipper<http://en.wikipedia.org/wiki/Zipper_%28data_structure%29>(cf. this > explanation <http://www.haskell.org/haskellwiki/Zipper>) is a much better, > much more functional, generic and maintainable solution. > > Briefly, the way this works is to automate the calculation of a context > type, C(T), from a data type T. The context type will allow for the > representation of locations in an instance of T in terms of contexts and > holes. There's a natural way to get from contexts to paths. So, there's a > natural map from URLs (viewed as paths) to locations. One great example of > how this works in practice is Oleg Kiselyov's Zipper-based file system. The > analogy between paths to files and URLs to resources should be clear. > > This has led me to look at where to cut the line on calculating zippers. As > the wikipedia article mentions above, it is possible do this completely > generically, provided one has a notion of differentiation on data > structures; that is, the zipper can be expressed in terms of the derivative > of a data structure. There are two natural (and somewhat competing) places > to hang the differentiation calculation: > > - the new collections library for scala > - the target of a mapping from one of the XML schema proposals to scala > types > > Jorge and i were chatting about this the other day. Either route is a bit > of a large task and i've got a bunch of other stuff on my plate right now. > However, i'd be very happy to collaborate with anyone who wants to make this > happen. Also, by the way, this works really well with a lot of other > monadically based machinery. > > Best wishes, > > --greg > > > On Fri, Jul 17, 2009 at 8:17 AM, TylerWeir <tyler.w...@gmail.com> wrote: > >> >> >>Wait a few days, and I think there'll be some very good news on this >> front. >> >> Tease! :) >> >> On Jul 17, 10:51 am, David Pollak <feeder.of.the.be...@gmail.com> >> wrote: >> > There are benefits to both approaches. I prefer the partial function >> > composition, but annotations on Pojos have their place. >> > Wait a few days, and I think there'll be some very good news on this >> front. >> > >> > On Fri, Jul 17, 2009 at 7:28 AM, Timothy Perrett >> <timo...@getintheloop.eu>wrote: >> > >> > >> > >> > >> > >> > > Hey guys, >> > >> > > I've been taking a look at Jersey and how it operates with Lift by way >> > > of the recent integration that cropped up on dev.java.net... >> > >> > > From my perspective, I see how having a standard RS service framework >> > > could be helpful, but it appears to bypass important lift concepts >> > > like SiteMap etc so I'm just wondering what the benefit of using such >> > > a layer would be over using DispatchPF etc to create REST services or >> > > serving xml fragments for templates? (I have no idea about Jersey >> > > apart from the basic docs ive read, so if im missing a major benefit >> > > id love to hear discuss) >> > >> > > Cheers for any thoughts >> > >> > > Tim >> > >> > -- >> > Lift, the simply functional web frameworkhttp://liftweb.net >> > Beginning Scalahttp://www.apress.com/book/view/1430219890 >> > Follow me:http://twitter.com/dpp >> > Git some:http://github.com/dpp >> >> >> > > > -- > L.G. Meredith > Managing Partner > Biosimilarity LLC > 1219 NW 83rd St > Seattle, WA 98117 > > +1 206.650.3740 > > http://biosimilarity.blogspot.com > -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Lift" group. To post to this group, send email to liftweb@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=en -~----------~----~----~----~------~----~------~--~---
