David, sounds reasonable.
So being able to call prepend/append after boot() makes no sense. In the light of htis, it shouldn't be possible to call the prepend/append outside of boot. I suggest my approach described previously. (Injecting an initialization context into boot and use that to configure LiftRules, then we don't expose the mutativity in LiftRules. Result: No runtime exceptions, no confusion on when to configure the webapp etc. Input? Cheers, Viktor On Sun, Dec 14, 2008 at 3:41 PM, David Pollak <feeder.of.the.be...@gmail.com > wrote: > Folks, > > I have not had a single instance of wanting to change global application > behavior at runtime. I cannot think of use case for such a feature. > > On the other hand, the idea that your program behavior is stable from the > first HTTP request on makes a lot of sense to me. It means tests work > because the tests don't have to worry about the behavior of the program > changing. The same n steps will lead to the same result. > > If anyone can come up with a use case for globally changing program > behavior during program execution, I'm all ears, but barring that, once the > boot phase is over, the stuff in LiftRules should be frozen. > > Thanks, > > David > > > > On Sun, Dec 14, 2008 at 3:54 AM, Marius <marius.dan...@gmail.com> wrote: > >> >> >> >> On Dec 14, 12:53 pm, "Viktor Klang" <viktor.kl...@gmail.com> wrote: >> > On Sun, Dec 14, 2008 at 11:42 AM, Marius <marius.dan...@gmail.com> >> wrote: >> > >> > > On Dec 14, 12:10 pm, "Viktor Klang" <viktor.kl...@gmail.com> wrote: >> > > > On Sun, Dec 14, 2008 at 9:28 AM, Marius <marius.dan...@gmail.com> >> wrote: >> > >> > > > > On Dec 14, 3:02 am, "Jorge Ortiz" <jorge.or...@gmail.com> wrote: >> > > > > > Not to beat a dead horse, but... what's the rationale, again, >> for >> > > > > throwing >> > > > > > an exception after boot? Is there a real danger to some or all >> > > RulesSeqs >> > > > > > being mutable after boot? If some, then those rules should >> > > selectively be >> > > > > > protected. Even if they're all dangerous, there are better >> (i.e., >> > > type >> > > > > safe) >> > > > > > ways of protecting RulesSeqs from mutation than just throwing an >> > > > > exception. >> > >> > > > > This was actually DPP's suggestion. I'm not sure why would someone >> > > > > mutate them after boot but I'm totally opened if there is a strong >> > > > > case for allowing that. I do not have strong feelings about this >> so >> > > > > changing it would be trivial. Still I kind of like it this way. >> What >> > > > > other ways of protecting mutations after boot are you referring? >> ... >> > > > > something like ignore it and do nothing? >> > >> > > > Hmm, how about "locking" them by havign a paralell lazy val? >> > >> > > > val somePf : RuleSeq = Nil; >> > >> > > > lazy val runtimeSomePf = somePf.toList >> > >> > > > Then prepending/appending on the somePf AFTER runtimeSomePf has been >> > > > dereferenced won't make a difference. >> > > > (runtimeSomePf would be used by Lift internally if that isn't clear >> > > enough >> > > > :) ) >> > >> > > Still we'd allow useless strong references on those lists. >> > >> > > > Or another, perhaps more suitable suggestion: >> > >> > > > make boot() have an InitializationContext parameter that's only >> available >> > > in >> > > > the scope of boot, and then the problem should disappear? >> > >> > > How would the problem disappear? ... I mean after boot people would >> > > still be able to add their functions (from API perspective) and they >> > > would be surprised that their functions are not called and yet lift >> > > just allowed them to do that. >> > >> > I meant something like: >> > >> > def boot(val lc : LiftContext) = >> > { >> > //prepend/append,configure everything on lc >> > >> > } >> > >> > And then when the LiftFilter runt boot: >> > >> > { >> > val lc = LiftContext(/*servletContext and stuff goes here*/) >> > boot(lc) >> > LiftRules.init(lc) >> > >> > } >> > >> > And then only have non-append/prependable stuff in LiftRules? >> > >> > But really, what is it a problem that lift is reconfigurable during >> runtime? >> > I thought that was kind of cool? >> >> As I said I don't have strong opinions on this. It was DPP's >> suggestion and personally I kind of like it which does not mean that >> things can not change :) ... AFAIC reconfiguration at runtime does not >> make a whole lot of sense because: >> >> 1. We'd have to expose other functions to allow people to also remove >> their function not only prepend & append them >> 2. I do not see what kinds of problems runtime reconfiguration really >> solve (I'm only referring on the current RulesSeq members). I haven't >> encounter a practical need but if you have please let me know. >> 3. Dynamic behavior can happen inside user's functions without >> allowing runtime reconfiguration. >> >> Just my 2 cents ... >> >> P.S. >> If the general consensus is to remove this restriction I have no >> problem removing it ... so more thoughts/perspectives on this are >> welcomed. >> >> >> >> > >> > Cheers, >> > Viktor >> > >> > >> > >> > >> > >> > > > Cheers, >> > > > Viktor >> > >> > > > > > Nit-pick: why is 'toList' (which just returns 'rules') defined >> as >> > > > > > private[http] when 'rules' itself is public? >> > >> > > > > Why would you use toList in the lift app code? ...RulesSeq is >> mainly >> > > > > about adding user functions to lift. If "rules" itself is public >> > > > > doesn't necessary mean that it should not have its "private" >> logic. >> > >> > > > > > Also, if RulesSeq are always made up of either Functions or >> > > > > > PartialFunctions, maybe we should enforce that at a type level, >> and >> > > the >> > > > > > helper methods on Seqs of PFs that now exist in the NamedPF >> object >> > > can be >> > > > > > put in the RulesSeq object. >> > >> > > > > But what would be the benefit? .. except that it would simplify a >> bit >> > > > > how Lift calls these PF's? >> > >> > > > > ... to me distinguishing between functions and partial functions >> here >> > > > > by using Either or even using different RulesSeq traits would not >> > > > > bring much benefits ... but I hope I'm wrong. >> > >> > > > > > --j >> > >> > > > > > On Sat, Dec 13, 2008 at 2:31 PM, Marius < >> marius.dan...@gmail.com> >> > > wrote: >> > >> > > > > > > All, >> > >> > > > > > > I committed a bunch of changes in LiftRules. In a previous >> thread >> > > > > > > Jorge suggested the abstraction of LiftRules variables. Lists >> of >> > > > > > > functions are now abstracted by RulesSeq trait, which contains >> > > prepend >> > > > > > > and append functions. Note that if you're calling >> prepend/append >> > > > > > > functions after boot they will throw an exception. If there >> are >> > > > > > > compelling reasons not to do this please let us know. This is >> just >> > > a >> > > > > > > mechanism to enforce the use of these functions on startup. >> > >> > > > > > > Br's, >> > > > > > > Marius >> > >> > > > -- >> > > > Viktor Klang >> > > > Senior Systems Analyst >> > >> > -- >> > Viktor Klang >> > Senior Systems Analyst >> >> > > > -- > Lift, the simply functional web framework http://liftweb.net > Collaborative Task Management http://much4.us > Follow me: http://twitter.com/dpp > Git some: http://github.com/dpp > > > > > -- Viktor Klang Senior Systems Analyst --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---