Hi Reid,
> On May 21, 2016, at 11:44 PM, Reid McKenzie <m...@arrdem.com> wrote: > > You should be able to do this: > > (defn f [a ^bytes b ^bytes c] > (if (instance? ByteBuffer a) > (.f binding ^ByteBuffer a b c) > (.f binding ^bytes a b c))) > > > You have a bimorphic function and yes there isn't a way to express that with > Clojure's calling convention and consequent hinting support. So 1) yes, 2) no > but no promises there, 3) see above. Thanks! That confirms my suspicions. Unfortunately, I was hoping to solve this statically. Since some of these call sites are really only useful internally, I’ll deal with the multi-var version, because my library’s the only one to pay that cost. thanks! lvh > I don't have a Clojure instance handy, but this should compile to > 1) load the a argument > 2) check instanceof against the class ByteBuffer > 3) branch to the appropriate instance invoke > 4) load b, c, a, from the arguments (as Objects), checkcasting appropriately > to get typed as hinted values on the stack > 5) invoke (fully type qualified, no reflection). > > On Saturday, May 21, 2016 at 4:57:43 PM UTC-5, lvh wrote: > Hi, > > > > I’m working on caesium[1], Clojure bindings for libsodium using jnr-ffi. Up > until recently, I was able to stick to byte arrays for all APIs; but I’ve > started writing new nonce-misuse resistant cryptosystems[2], so I need to > have some byte-level layout within a byte array. I’m using > java.nio.ByteBuffer to provide mutable byte array “views” on top of an > existing byte array. > > The underlying C API takes (const) char *s. jnr-ffi understands how to > translate both byte[] and ByteBuffer to char *. Previously, I had functions > like: > > (defn f > [^bytes a ^bytes b ^bytes c] > (.f binding a b c)) > > All was well; no reflection. However, now `binding` has two signatures for f: > [byte[] byte[] byte[]] and [ByteBuffer byte[] byte[]]. If I remove the first > ^byte annotation, everything works well, but this generates reflection > warnings. > > 1. Does this reflection warning mean that there will be actual reflection if > the type is known at the call site? (I believe the answer is “yes”.) > 2. Does that change with AOT? > 3. Is there a way to keep the same fn name, e.g. have: > > (defn f > [a ^bytes b ^bytes c] > (.f binding a b c)) > > … without reflection, as long as all callers of f have the type of `a` > statically determined? Again, I’m assuming the answer here is “no”, because > this resolution is done locally. > > I can solve this in a macro since the two definitions are identical except > for the type hint, but I’d first just like to check that I’m not missing some > of the finer points of Java interop/type hinting. Also, does this mean that I > necessarily have two fns with different names, one for each signature? E.g.: > > (defn f-bytes > [^bytes a ^bytes b ^bytes c] > (.f binding a b c)) > > (defn f-bytebuffer > [^java.nio.ByteBuffer a ^bytes b ^bytes c] > (.f binding a b c)) > > I know that having two overloads with the same arity doesn’t work, so I’m > guessing the answer is “no" there as well :-( > > > Thanks in advance! > lvh > > [1]: https://github.com/lvh/caesium <https://github.com/lvh/caesium> > [2]: https://www.lvh.io/posts/nonce-misuse-resistance-101.html > <https://www.lvh.io/posts/nonce-misuse-resistance-101.html> > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > <http://groups.google.com/group/clojure?hl=en> > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com > <mailto:clojure+unsubscr...@googlegroups.com>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
