Eric Kow <[email protected]> added the comment: On Thu, Aug 05, 2010 at 11:50:24 +0000, Eric Kow wrote: > > Thu Jul 15 11:38:42 CEST 2010 Petr Rockai <[email protected]> > > * Resolve issue1892: Improve safety of makeBundle* and fix a couple of > > related bugs.
Got some feedback on IRC from Petr, so I'll apply this. > QUESTION: So then there's the question of why we have to seal off the > ending state of the common patches in fetchPatches. Shouldn't we be > able to keep track of the fact that the common end in the same place as > the us/them patches begin? >From http://irclog.perlgeek.de/darcs/2010-08-05#i_2667135 kowey: mornfall: a bit of patch305 went over my head could you explain why we need to seal off the ending state of common in fetchPatches? I think I understand that the unsafeCoerceEndP in makeBundle (Darcs.Commands.Pull) is just a straightforward consequence of the sealing off ... mornfall: kowey: I think the answer here is that the :\/: has no start state, so the end state of the stuff before :\/: won't be very useful anyway. :\/: works as a seal for the start states IIUIC So I think that's why I sealed the endstate of common (since there's nothing to pair it up with...) kowey: I think I still have trouble reading and interpreting data (a1 :\/: a2) C(x y) = FORALL(z) (a1 C(z x)) :\/: (a2 C(z y)) I mean, even if we knock out the macros: data (a1 :\/: a2) cX cY = forall cZ . (a1 cZ cX) :\/: (a2 cZ cY) [a few moments later] kowey: oh ok, actually maybe I don't have any issue reading that so it's just (:\/:) :: forall cZ . a1 cZ cX -> a2 cZ cY -> (a1 :\/: a2) cX cY and like you're saying, no start state... that sound right? mornfall: Yes. • kowey buys it... Eric (I think I find GADT-style syntax less confusing than traditional because it involves me doing fewer substitutions in my head...) -- Eric Kow <http://www.nltg.brighton.ac.uk/home/Eric.Kow> For a faster response, please try +44 (0)1273 64 2905. ---------- title: Resolve issue1892: Improve safety of makeBundle* and fix a couple of -> Resolve issue1892: Improve safety of makeBundle* and fix a couple of __________________________________ Darcs bug tracker <[email protected]> <http://bugs.darcs.net/patch305> __________________________________ _______________________________________________ darcs-users mailing list [email protected] http://lists.osuosl.org/mailman/listinfo/darcs-users
