I hope I don't wander too far off-topic here as I wend my way to the
question at the end of this post ("would it be useful to look at
something like the OWL/SWRL web ontology and rule languages for
liftweb?").I tend to generalize/abstract a lot - so if anyone with a theoretical bent is willing to peruse the following, I would appreciate any feedback as to whether it could be applicable to liftweb. Basically I just want to wonder out loud here whether support in liftweb for some of the specific ideas referenced in this thread (particularly the "keeping the meaning with the bytes" thing) could be helped along by looking at some possibly related theoretical work being done involving contexts and policies for web services, eg here: http://www.csee.umbc.edu/swpw/papers/ PDF! - http://www.csee.umbc.edu/swpw/papers/denker.pdf Some of this admittedly "theoretical" work from this particular conference is being implemented in machine-executable languages (eg, Maude) which are also fortunately quite close to Scala, thanks to Scala's support for both the functional and the object-oriented programming paradigms. (Maude is similar to Haskell and ML, which are sometimes also compared to Scala.) This means that it might be quite straightforward to map any needed portions of this related theoretical work on policies and contexts for web services from languages such as Maude to liftweb in a fairly straightforward manner. ((Full disclosure: Maude is one of the few languages I know and use, eg for conceptual data modeling of entity-relationship databases: http://www.springerlink.com/content/35gxk6g83vn6q648/ I mention this mainly to show that although I'm still a relative newbie when it comes to web frameworks - particularly regarding security - I do have some background in specification of databases with contraints which I hope could somehow be applicable to database- oriented programming in liftweb.)) I was intrigued by the 2006 post by DP mentioned upthread: http://blog.lostlake.org/index.php?/archives/19-Keeping-the-meaning-with-the-bytes.html where he suggests some excellent web framework design principles: - "The semantic meaning of fields on objects should be retained throughout the field's life." - "Conversion to a semantic-free format (String, double, etc.) should be done as late in the field's life-cycle (e.g., a String returned from 'render as HTML') as possible." - "Every field of every object {should} be semantically meaningful." - - "getSSN() returns an object of SSN class that derives from Taxpayer class that derives from SensitiveIndentifyingInformation class." - - "the toHtml() method on the SSN class returns '***-**-****' unless the context in which the SSN is being accessed has permissions / grants permissions to see more." - "All pieces of the object are defined in a central place." It would just seem that the above-postulated "central place" could be (built using some of the rich facilities provided by) Scala's type system itself - perhaps even neatly packaged into a kind of "liftweb MOP" (meta object protocol, like CLOS added to Lisp), or presented as a DSL (domain-specific language). The road from design-time to run-time is of course a sequence of stages where abstraction is concretized and type info is erased - as we move from an SSN, to a String, and eventually to a bunch of pixels on the screen. I would think that the line could be drawn so that the web framework always "knows" that something is an SSN. I don't know enough about JVMs to understand if or when this kind of "type info" is eventually "erased" - but I understand that it's important that a level of abstraction should be provided to the end-programmer using a web framework where this type info is always available, enabling centrally specified policies to make the web app just "do the right thing" depending on the particular context. Coming back to the problem of providing a completely general framework for specifying policies and contexts: Would any of the theoretical papers from, say, this conference: http://www.csee.umbc.edu/swpw/papers/ provide any useful pointers as to how to approach this? I'm not sure if the implementation languages there seem too ivory- tower, or the conceptual languages there sound too "designed by committee" (eg, OWL/SWRL), in the eyes of liftweb committers and programmers who might be quite understandably up to their necks in hands-on issues like cross-site scripting attacks etc. But formal, theoretical stuff can have its place, since: (a) Scala itself is based on a rigorous theoretical, formal foundation (b) tools supporting checking of programs written in commercial/ industrial languages (eg, Erlang) are now being written in formal/ academic languages (eg, Maude): (WARNING - PS file!) http://www-i2.informatik.rwth-aachen.de/old/Staff/Current/neuhaeusser/publications/wrla06.ps And Scala's fuctional/object-oriented paradigms and very rich type system (making Scala very close to many formal/academic languages) could make it straightforward to map code and concepts from some of these languages and systems to Scala and liftweb. For example, one of these papers: PDF! http://www.csee.umbc.edu/swpw/papers/denker.pdf "Towards Integrated Specification and Analysis of Machine-Readable Policies Using Maude" by Rukman Senanayake, Grit Denker and Jon Pearce uses the executable specification language Maude (which, like Scala, supports both functional and object-oriented programming paradigms, pattern matching, type parameterization, per-operator user-definable evaluation strategies, and reflection) to provide an executable specification for an example of a web service which processes returns for Amazon. Would it be useful to look at stuff like the "OWL-S" process model and "OWL/SWRL" web ontology and rule languages used in the above paper, as a point of reference for providing a more general set of facilities for dealing with policies and contexts in liftweb? On Oct 6, 1:50 pm, "Oleg G." <ojo...@gmail.com> wrote: > Thanks for all the answers and especially for David's clarification. > It would be really cool to upgrade the 'keeping the meaning with the > bytes' thing (http://blog.lostlake.org/index.php?/archives/19-Keeping- > the-meaning-with-the-bytes.html) to allow extension/customization. > > > > > Generally, yes. I haven't dived into the reflection-based layout or the > > Scala-related reflection stuff in 2.8 deeply enough to say that we could do > > a val-based Record implementation. > > > > Is there any reason (other than time constraints) to not update the Record > > > framework to take advantage of the newer language features? > > > > Tim > > > -- > > Lift, the simply functional web frameworkhttp://liftweb.net > > Beginning Scalahttp://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 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 -~----------~----~----~----~------~----~------~--~---
