Witx replaced the cap'n proto proposal https://github.com/WebAssembly/WASI/blob/master/docs/witx.md
On Fri, Apr 24, 2020 at 12:40 AM <[email protected]> wrote: > Did anything every come of this? > > On Sunday, June 16, 2019 at 6:45:40 AM UTC-7, Mark S. Miller wrote: >> >> (From Martin BZ and MarkM jointly) >> >> Hi Kenton, could you look at >> >> https://github.com/wanderer/WASI/tree/master/schema >> >> We want to suggest this to the WASI folks, to suggest that this be the >> way WASI IDLs should be specified. Their current plans are to start with >> WebIDL, which is rather horrible. So we'd like to send this to them as soon >> as reasonable, but not sooner. So, at this stage, we're not looking for >> detailed feedback on particulars, but rather, whether this is a reasonable >> style for using the Cap'n Proto schema language. >> >> Thanks! >> >> >> >> On Sun, Jun 16, 2019 at 10:37 AM Mark S. Miller <[email protected]> wrote: >> >>> [+Michael, +Dan] >>> >>> I like this direction! >>> >>> Where can I find a bnf for the Cap'n Proto schema/idl language? I want >>> to start from there to create a concrete syntax for the Chainmail (formal >>> specification language for ocap patterns) abstract syntax. I had previously >>> started with a Jessie-like syntax, but I think Cap'n Proto would be a >>> better place to start. As part of this, I want to write specifications for >>> the ERTP and SwingSet APIs as Cap'n Proto files that I can imagine would >>> grow into Chainmail specs. Together with WASM/WASI bindings for Cap'N >>> Proto, this would be a start for enabling non-JS WASM instances to plug >>> into our SwingSet kernel. >>> >>> To close this loop, we should define the subset of Cap'n Proto that we >>> expect to compile to WASM/WASI bindings. SwingSet should then restrict >>> itself to that subset. >>> >>> Is there a standard representation of the AST that a Cap'n Proto >>> schema/idl file parses into? With such an AST translated to JSON, I would >>> also like to explore changing our marshaling system so that it only allows >>> through calls described in the IDL and made available to the comm system at >>> runtime via a derived JSON representation suitable for that purpose. That >>> would put us in a good position to explore eventually cerealizing to Cap'n >>> Proto itself. >>> >>> >>> >>> On Sat, Jun 15, 2019 at 6:46 PM 'Kenton Varda' via Cap'n Proto < >>> [email protected]> wrote: >>> >>>> Hi mjbecze, >>>> >>>> This is interesting! Is this related to: >>>> >>>> https://github.com/WebAssembly/design/issues/1274 >>>> >>>> ? >>>> >>>> On Sat, Jun 15, 2019 at 9:08 AM <[email protected]> wrote: >>>> >>>>> Hello, >>>>> I'm currently investigating whether capt'n proto schema would be >>>>> appropriate for describing Webassebly interfaces. I'm attempting to >>>>> translate this interface >>>>> <https://github.com/WebAssembly/WASI/blob/master/docs/WASI-overview.md> >>>>> to capn proto schema. I several questions and I'm sure I'll have more as >>>>> the work progresses. >>>>> >>>>> 1. Webassebly will soon have opaque references >>>>> <https://github.com/WebAssembly/reference-types>. How would you >>>>> represent reference types in capt'n proto? >>>>> >>>> >>>> Cap'n Proto's "Capability" type is exactly what you want here: it >>>> represents an external reference to "something". Note that interface types >>>> in Cap'n Proto are all subclasses of "Capability" -- i.e. "Capability" is >>>> kind of like Java's "Object". But it's totally valid to use just the type >>>> "Capability" to represent a handle to some opaque thing that has no >>>> particular methods you can call. >>>> >>>> Also worth noting that in Cap'n Proto's real RPC system, capabilities >>>> are referenced through table indices, just like Wasm opaque references >>>> apparently will be. Check out: >>>> >>>> >>>> https://github.com/capnproto/capnproto/blob/77f20b4652e51b5a7ebda414e979e059a6c7c27c/c++/src/capnp/rpc.capnp#L116 >>>> >>>> Also, Cap'n Proto's C++ implementation has the ability to attach file >>>> descriptors to capabilities and pass them between processes (via SCM_RIGHTS >>>> on unix sockets): >>>> >>>> https://github.com/capnproto/capnproto/pull/821 >>>> >>>> So there's lots of precedent here. >>>> >>>> 2. Is annotation the correct way to represent pointers? for example >>>>> >>>> >>>> Oof, this is pretty awkward, especially in that it presumes the callee >>>> has the ability to reach into the caller's address space. Obviously, Cap'n >>>> Proto hasn't been designed with that sort of thing in mind. >>>> >>>> With that said, I like your second solution, transforming return values >>>> into things that are stored to the pointer. This allows the schema to >>>> express the semantics in a way that makes sense for classic RPC, and then >>>> return-by-write-to-pointer becomes part of the "calling convention" that >>>> maps Cap'n Proto to Wasm. >>>> >>>> -Kenton >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Cap'n Proto" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> Visit this group at https://groups.google.com/group/capnproto. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/capnproto/CAJouXQ%3DYWW-L4Rp5JZHD5CGTbhiKypWuoP5HJ10CxKqL8A6Z%3Dg%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/capnproto/CAJouXQ%3DYWW-L4Rp5JZHD5CGTbhiKypWuoP5HJ10CxKqL8A6Z%3Dg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> >>> >>> -- >>> Cheers, >>> --MarkM >>> >> >> >> -- >> Cheers, >> --MarkM >> > -- > You received this message because you are subscribed to a topic in the > Google Groups "Cap'n Proto" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/capnproto/faUdrdqBVtI/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/capnproto/e9ee73e2-9950-45f6-ba83-c8864f217a32%40googlegroups.com > <https://groups.google.com/d/msgid/capnproto/e9ee73e2-9950-45f6-ba83-c8864f217a32%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. 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