Thanks to a colleague who introduced me to Nim during last week’s SUSE Labs conference, I became a man with a dream, and after fiddling with compiler flags and obviously not reading documentation, I finally made it.

This is something that shouldn’t exist; from the list of ideas that should never have happened.

But it does. It’s a Perl interpreter embedded in Rust. Get over it.

Once cloned, you can run the following commands to see it in action:

  • cargo run --verbose -- hello.pm showtime
  • cargo run --verbose -- hello.pm get_quick_headers

How it works

There is a lot of autogenerated code, mainly for two things:

  • bindings.rs and wrapper.h; I made a lot of assumptions and perlxsi.c may or may not be necessary in the future (see main::xs_init_rust), depends on how bad or terrible my C knowledge is by the time you’re reading this.
  • xs_init_rust function is the one that does the magic, as far as my understanding goes, by hooking up boot_DynaLoader to DynaLoader in Perl via ffi.

With those two bits in place, and thanks to the magic of the bindgen crate, and after some initialization, I decided to use Perl_call_argv, do note that Perl_ in this case comes from bindgen, I might change later the convention to ruperl or something to avoid confusion between that a and perl_parse or perl_alloc which (if I understand correctly) are exposed directly by the ffi interface.

What I ended up doing, is passing the same list of arguments (for now, or at least for this PoC), directly to Perl_call_argv, which will in turn, take the third argument and pass it verbatim as the call_argv

        Perl_call_argv(myperl, perl_sub, flags_ptr, perl_parse_args.as_mut_ptr());

Right now hello.pm defines two sub routines, one to open a file, write something and print the time to stdout, and a second one that will query my blog, and show the headers. This is only example code, but enough to demostrate that the DynaLoader works, and that the embedding also works :)

itsalive

I got most of this working by following the perlembed guide.

Why?

Why not?.

I want to see if I can embed also python in the same binary, so I can call native perl, from native python and see how I can fiddle all that into os-autoinst

Where to find the code?

On github: https://github.com/foursixnine/ruperl or under https://crates.io/crates/ruperl