Hi Kenton, The project comes with a whole new parser and layouting implementation. I have some tests[1] for complicated struct/union layouts, but you're absolutely right that this needs much more rigorous testing and an enormous disclaimer - both of which I had planned had I continued.
It's not possible to invoke external programs or call into other languages from Zig comptime[2], that would require a separate build step. One idea I considered is to have the parser recognize the comments generated by `capnp -o capnp` and use them for validation, so that it's at least easier to get that extra assurance. Loading a file in schema.capnp format could also be done, of course, but then one might as well introduce a separate build step. 1) https://code.blicky.net/yorhel/capnzig/src/commit/5618819e01c8dda38962b986e4107d7d20e863f5/src/schema.zig#L812 2) Okay, Zig's comptime being turing complete one could potentially write a C++ interpreter and run capnp's layouting code during Zig compilation, but let's not go there. :) Yorhel. On 2023-01-30, 'Kenton Varda' via Cap'n Proto wrote: > Hi Yorhel, > > Cool stuff. It's neat that Zig can run code at compile time. > > Question, though: are you calling the C++ parser library to parse Cap'n > Proto schema language, or did you write a whole new parser for it? If the > latter, I'm worried as the algorithm to decide the layout of structs is > quite complex, especially when unions of groups are involved. If you are > re-implementing that, it would be pretty easy to get wrong leading to > subtle incompatibilities. Is it possible to invoke the parser from the C++ > implementation as a library, to convert from capnp IDL into schema.capnp > format, which could then be interpreted by your implementation? > > -Kenton > > On Thu, Jan 12, 2023 at 6:06 AM 'Yorhel' via Cap'n Proto < > capnproto@googlegroups.com> wrote: > > > Hi list, > > > > I've been working on a Cap'n Proto implementation for the Zig language. > > This implementation is unusual in that it leverages the language's > > compile-time code execution capabilities to read a schema file - written > > in Cap'n Proto's schema language, no separate compilation step required > > - and then make the interfaces defined in the schema available to > > library users. > > > > I wasn't 100% sure if this was going to work, but I now have a parser, > > struct layouting algorithm and some rudimentary experiments with a > > type-safe struct read/write API that compiles down to code that *should* > > be just as efficient as if a code generation step was involved. > > > > Sadly, now that I've convinced myself that this might actually work out, > > I've lost the motivation to do the remaining 80% of the work and turn it > > into a usable library. So instead I'm publishing the unfinished product > > with the hope that it might inspire or prove useful to someone. And, who > > knows, maybe I'll continue to work on it some time in the future. > > > > The code is at https://code.blicky.net/yorhel/capnzig > > > > Documentation's kind of lacking - the code is commented here and there, > > but making sense of everything may take effort. I'll be around to answer > > questions if there are any. > > > > Here's hoping we'll have a mature Cap'n Proto implementation for Zig at > > some point, regardless of which code generation strategy is taken. > > > > Yorhel. > > > > -- > > 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 capnproto+unsubscr...@googlegroups.com. > > To view this discussion on the web visit > > https://groups.google.com/d/msgid/capnproto/Y7/3v1VZfkFIFO5s%40gmai021. > > > > -- > 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 capnproto+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/capnproto/CAJouXQ%3DFvmUpqCvqEtGAvU4gtMo5V8drrGcPHXWRuPBYc254PA%40mail.gmail.com. -- 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 capnproto+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/capnproto/Y9jOyhsNXGK3areQ%40gmai021.
