Hi, Rustler seems to be very promising but unfortunately I am not able to compile it.

OS: Mac OS X siera Rust Version: 1.12.0.

The error I am getting is:

$ cargo build
    Updating registry `https://github.com/rust-lang/crates.io-index`
   Compiling easy-plugin-plugins v0.9.1
error: no method named `pat_enum` found for type `&mut syntax::ext::base::ExtCtxt<'_>` in the current scope
   --> /Users/tomaskorcak/dev/microcrawler/gauc-elixir/native/gauc/target/debug/build/easy-plugin-plugins-64578d19b8e93d12/out/lib.rs:624:23
    |
624 |     let pat = context.pat_enum(span, path, pats);
    |                       ^^^^^^^^
/Users/tomaskorcak/.cargo/registry/src/github.com-1ecc6299db9ec823/easy-plugin-plugins-0.9.1/src/lib.rs:36:1: 36:47 note: in this expansion of include!

error: aborting due to previous error

error: Could not compile `easy-plugin-plugins`.

To learn more, run the command again with --verbose.

Hi 👋

While using Rustler, I've wanted to use more complex enum types for Elixir bindings. So I tried to implement it, which can be used like the following snippet.

#[derive(rustler::NifEnum)]
enum Test {
  Foo{ x: i32, y: i32 }, // Allow named enum
  Bar(String),
  Baz(String),  // Allow duplicated types
  Qux
}

#[rustler::nif]
fn claim_test(value: i32) -> Test {
  match value {
    0 => Test::Foo{ x: 1, y: 2 },        // %{__enum__: :foo, x: 1, y: 2}
    1 => Test::Bar("Hello".to_string()), // {:bar, "Hello"}
    2 => Test::Baz("world".to_string()), // {:baz, "world"}
    3 => Test::Qux,                      // :qux
    _ => panic!("")
  }
}

If there are more idiomatic ways to bind, please let me know!

Also, I didn't realize there was a related issue, #426. I'm really sorry about that 🙏

Not sure if this is a OS X-specific issue:

Cargo.toml

[package]
name = "rustler_test"
version = "0.1.0"
authors = []

[lib]
name = "rustler_test"
path = "src/nif.rs"
crate_type = ["dylib"]

[dependencies]
rustler = "0.8.1"
rustler_codegen = "0.8.1"

src/nif.rs

#![feature(plugin)]
#![plugin(rustler_codegen)]

#[macro_use]
extern crate rustler;
use rustler::{ NifEnv, NifTerm, NifResult, NifEncoder };

rustler_export_nifs!(
    "Elixir.RustlerTest",
    [("add", 2, add)],
    None
);

fn add<'a>(env: &'a NifEnv, args: &Vec<NifTerm>) -> NifResult<NifTerm<'a>> {
    let num1: i64 = try!(args[0].decode());
    let num2: i64 = try!(args[1].decode());
    Ok((num1 + num2).encode(env))
}

$ multirust run nightly-2016-04-05 mix rustler.check
Rustler environment verified
$ multirust run nightly-2016-04-05 cargo build
   Compiling lazy_static v0.1.16
   Compiling easy-plugin v0.3.0
   Compiling aster v0.14.0
   Compiling libc v0.2.10
   Compiling ruster_unsafe v0.4.0
   Compiling rustler v0.8.1
   Compiling rustler_codegen v0.8.1
   Compiling rustler_test v0.1.0 (file:///Users/brendan/code/dev-day/elixir_rustler_test)
error: linking with `cc` failed: exit code: 1
note: "cc" "-m64" "-L" "/Users/brendan/.multirust/toolchains/nightly-2016-04-05/lib/rustlib/x86_64-apple-darwin/lib" "/Users/brendan/code/dev-day/elixir_rustler_test/target/debug/rustler_test.0.o" "-o" "/Users/brendan/code/dev-day/elixir_rustler_test/target/debug/librustler_test.dylib" "/Users/brendan/code/dev-day/elixir_rustler_test/target/debug/rustler_test.metadata.o" "-Wl,-dead_strip" "-nodefaultlibs" "-L" "/Users/brendan/code/dev-day/elixir_rustler_test/target/debug" "-L" "/Users/brendan/code/dev-day/elixir_rustler_test/target/debug/deps" "-L" "/Users/brendan/.multirust/toolchains/nightly-2016-04-05/lib/rustlib/x86_64-apple-darwin/lib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/librustler-12f16f7939d96e54.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/libruster_unsafe-badf32d60ecc0604.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/liblibc-30c6b6751f89189b.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/liblazy_static-5e6d9f365bf63baa.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/libstd-18402db3.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/libcollections-18402db3.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/librustc_unicode-18402db3.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/librand-18402db3.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/liballoc-18402db3.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/liballoc_system-18402db3.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/liblibc-18402db3.rlib" "-Wl,-force_load,/var/folders/z3/g4m3xbnj11q6m76kzg8w683c0000gn/T/rustc.QBlM3AicSUqg/libcore-18402db3.rlib" "-l" "System" "-l" "pthread" "-l" "c" "-l" "m" "-dynamiclib" "-Wl,-dylib" "-l" "compiler-rt"
note: Undefined symbols for architecture x86_64:
  "_enif_make_double", referenced from:
      rustler::wrapper::nif_interface::enif_make_double::hd19548d32bb32295 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$f64$u20$as$u20$types..NifEncoder$GT$::encode::h706149e7449ffee2 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$f32$u20$as$u20$types..NifEncoder$GT$::encode::h144f24ce0170a8e0 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_get_ulong", referenced from:
      ruster_unsafe::enif_get_uint64::h64c3175e0dbcd390 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      ruster_unsafe::enif_get_uint64::h64c3175e0dbcd390 in libruster_unsafe-badf32d60ecc0604.rlib(ruster_unsafe-badf32d60ecc0604.0.o)
  "_enif_make_ulong", referenced from:
      ruster_unsafe::enif_make_uint64::h4fba0e724d8e25b6 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      ruster_unsafe::enif_make_uint64::h4fba0e724d8e25b6 in libruster_unsafe-badf32d60ecc0604.rlib(ruster_unsafe-badf32d60ecc0604.0.o)
  "_enif_make_long", referenced from:
      ruster_unsafe::enif_make_int64::hbc1979f2890ffe9c in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      ruster_unsafe::enif_make_int64::hbc1979f2890ffe9c in libruster_unsafe-badf32d60ecc0604.rlib(ruster_unsafe-badf32d60ecc0604.0.o)
  "_enif_get_uint", referenced from:
      rustler::wrapper::nif_interface::enif_get_uint::h5c5a16f0a01fde37 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$u32$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::haf5c58d5060cb07f in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$u8$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::h3e7e1bef75d03b42 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$u16$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::h1e7efa45cf0cba98 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_get_int", referenced from:
      rustler::wrapper::nif_interface::enif_get_int::hc379e848b0f1fa91 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$i32$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::h1c37e7be14e575ae in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$i8$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::ha035f42162eb16a1 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$i16$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::h5a81998157625a57 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_int", referenced from:
      rustler::wrapper::nif_interface::enif_make_int::h60d93b2ae4a8c8d3 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$i32$u20$as$u20$types..NifEncoder$GT$::encode::h7ddd4380fe5dda18 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$i8$u20$as$u20$types..NifEncoder$GT$::encode::hdc7675ac9b527c9f in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$i16$u20$as$u20$types..NifEncoder$GT$::encode::hb0da2bfd44111ec8 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_keep_resource", referenced from:
      rustler::wrapper::nif_interface::enif_keep_resource::hcf8953a093156f6c in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_release_resource", referenced from:
      rustler::wrapper::nif_interface::enif_release_resource::hcddf0787bf6dbeeb in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_atom_len", referenced from:
      rustler::wrapper::nif_interface::enif_make_atom_len::he20a8a9702701fff in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_get_resource", referenced from:
      rustler::wrapper::nif_interface::enif_get_resource::h47d539fa331c39f3 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_resource", referenced from:
      rustler::wrapper::nif_interface::enif_make_resource::hb81c16919c920cad in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_alloc_resource", referenced from:
      rustler::wrapper::nif_interface::enif_alloc_resource::h68237ee990d1cf46 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_uint", referenced from:
      rustler::wrapper::nif_interface::enif_make_uint::hfe8668de47444792 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$u32$u20$as$u20$types..NifEncoder$GT$::encode::h868c09d12496aeec in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$u8$u20$as$u20$types..NifEncoder$GT$::encode::h11ad232d66e87a7d in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$u16$u20$as$u20$types..NifEncoder$GT$::encode::h201a5388c8670d75 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_map_update", referenced from:
      rustler::wrapper::nif_interface::enif_make_map_update::hf5941f5f4b1d847b in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_get_map_value", referenced from:
      rustler::wrapper::nif_interface::enif_get_map_value::hc296d9a0bd30c233 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_map_put", referenced from:
      rustler::wrapper::nif_interface::enif_make_map_put::ha859d99862427ecd in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_open_resource_type", referenced from:
      rustler::wrapper::nif_interface::enif_open_resource_type::h12583a80f65f5745 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_new_map", referenced from:
      rustler::wrapper::nif_interface::enif_make_new_map::h907851f26b8541d0 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_badarg", referenced from:
      rustler::wrapper::nif_interface::enif_make_badarg::h4841a4ca720a65e5 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_get_tuple", referenced from:
      rustler::wrapper::nif_interface::enif_get_tuple::h7fd11d0d72fa7d45 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_get_long", referenced from:
      ruster_unsafe::enif_get_int64::hebc458f802f3215b in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      ruster_unsafe::enif_get_int64::hebc458f802f3215b in libruster_unsafe-badf32d60ecc0604.rlib(ruster_unsafe-badf32d60ecc0604.0.o)
  "_enif_get_map_size", referenced from:
      rustler::wrapper::nif_interface::enif_get_map_size::h3f9747fdd9d0f47c in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_tuple_from_array", referenced from:
      rustler::wrapper::nif_interface::enif_make_tuple_from_array::h7befd54d882d7531 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_map_remove", referenced from:
      rustler::wrapper::nif_interface::enif_make_map_remove::h961aa87e2152ef7f in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_is_atom", referenced from:
      rustler::wrapper::nif_interface::enif_is_atom::h334838d6a8353d15 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_copy", referenced from:
      rustler::wrapper::nif_interface::enif_make_copy::h810279a726029774 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_inspect_binary", referenced from:
      rustler::wrapper::nif_interface::enif_inspect_binary::h060c7c6692faf746 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      rustler::binary::NifBinary::from_term::h00da1e274a0cd422 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_alloc_env", referenced from:
      rustler::wrapper::nif_interface::enif_alloc_env::h3fd2c1de3d6068bc in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_make_binary", referenced from:
      rustler::wrapper::nif_interface::enif_make_binary::hdd6097cc32618309 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      rustler::binary::NifBinary::from_owned::h538759bc101b2b41 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_alloc_binary", referenced from:
      rustler::wrapper::nif_interface::enif_alloc_binary::h08bb424d3fa65f76 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      rustler::binary::OwnedNifBinary::alloc::hf56f1176ed8c3872 in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_release_binary", referenced from:
      rustler::wrapper::nif_interface::enif_release_binary::hcd3611ded3fa4e8e in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$binary..OwnedNifBinary$u20$as$u20$std..ops..Drop$GT$::drop::hce6f374d6af3cdab in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_get_double", referenced from:
      rustler::wrapper::nif_interface::enif_get_double::h0954e2466735bdec in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$f64$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::h3c4a4cbd31f2a5df in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
      _$LT$f32$u20$as$u20$types..NifDecoder$LT$$u27$a$GT$$GT$::decode::h7abf1a0ce08162cb in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
  "_enif_raise_exception", referenced from:
      rustler::wrapper::nif_interface::enif_raise_exception::hfb9038fb735943ae in librustler-12f16f7939d96e54.rlib(rustler-12f16f7939d96e54.0.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

error: aborting due to previous error
error: Could not compile `rustler_test`.

To learn more, run the command again with --verbose.

I did a google and your name came up! Did you ever have a quick stab at this? I have a feeling it would be very useful and much better than :mochiweb. With Rustler it should also be quite safe too.

The structure that Floki uses for parsed html looks about what we want out of html5ever and fairly simple...

[Modify the `mix.exs` file]

$ mix test
Compiling NIF crate :rustler_test (native/rustler_test)...
    Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
Compiling 221 files (.ex)

13:15:37.820 [warn]  The on_load function for module Elixir.RustlerTest returned:
{:error, {:upgrade, 'Upgrade not supported by this NIF library.'}}

[Tests fail]

[Then, running again works]

$ mix test

[Tests succeed]

To make it work in travis CI I had to compile before running the tests:

 - MIX_ENV=test mix compile
 - mix test || travis_terminate 1

Same issue happens when trying to open the console with: iex -S mix

Rustler compiler is in the recommended order: compilers: [:rustler, :phoenix, :gettext] ++ Mix.compilers,

Not sure if there is any way to actually fix this. This is probably because Erlang has stdout set to non-blocking mode, and a buffer gets filled up somewhere.

Hi, thanks for starting this great open source project!

Brief

I am using rustler as a nested dependency, and since v0.22.0rc, which I am using via pulling master branch, I think the new compilation approach doesn't copy the files correctly when creating a release. It works when I try to run the same release command twice or more, though.

Output

Code

defmodule DamaLogic.NifBridge do
  use Rustler, otp_app: :dama_logic, crate: "damalogic_damaprocess"

  [...]
end

Running mix release for the first time in a clean docker environment.

During compilation

226	
227	03:31:43.683 [warn]  The on_load function for module Elixir.DamaLogic.NifBridge returned:
228	{:error, {:load_failed, 'Failed to load NIF library: \'/work/_build/prod/lib/dama_logic/priv/native/libdamalogic_damaprocess.so: cannot open shared object file: No such file or directory\''}}
229	
230	Generated dama_logic app
231	

After compilation

Running find . -iname '*.so'

./deps/dama_logic/priv/native/libdamalogic_damaprocess.so

./_build/prod/rel/dama_server/lib/runtime_tools-1.14/priv/lib/trace_ip_drv.so
./_build/prod/rel/dama_server/lib/runtime_tools-1.14/priv/lib/dyntrace.so
./_build/prod/rel/dama_server/lib/runtime_tools-1.14/priv/lib/trace_file_drv.so
./_build/prod/rel/dama_server/lib/crypto-4.6.5/priv/lib/crypto.so
./_build/prod/rel/dama_server/lib/crypto-4.6.5/priv/lib/crypto_callback.so
./_build/prod/rel/dama_server/lib/crypto-4.6.5/priv/lib/otp_test_engine.so

./_build/prod/lib/dama_logic/native/damalogic_damaprocess/release/deps/libdamalogic_damaprocess.so
./_build/prod/lib/dama_logic/native/damalogic_damaprocess/release/deps/librustler_codegen-1426f88bc646ec0e.so
./_build/prod/lib/dama_logic/native/damalogic_damaprocess/release/libdamalogic_damaprocess.so

(Newlines added by me for clarity)

Expectation

I would expect the output of the *.so to be within the _build directory instead of the deps directory given that :build_embedded is set to true. If the priv copying is happening before compilation, I guess this would cause the issue of breaking only during the first attempt of generating a release?

I will attempt to make a small repro repo once I get around to it.

Thanks,

Implementation for built-in types:

Option::Some(value) is_encoded as value_encoded Option::None is encoded as :nil Result::Ok(value) is encoded as {:ok, value_encoded} Result::Err(err) is serialized as {:error, err_encoded}

$ mix rustler.check
** (Mix) NIF version 2.11 is not supported by Rustler. See https://github.com/hansihe/Rustler/blob/master/FAQ.md#unsuppored-nif-version

And yet I have Erlang 19, definitely not old by any stretch, although has been out for a while now.

The required version of rustc is only a week old, but still you are trying to use a version manager that is deprecated in favor of rustup for about half a year

Fixes #424 . I'm trying to implement support for generic/polymorphic types. Can you give me some feedback whether I'm on the right track? If yes, I'll proceed with the other macros.

This pull requests defines a MSRV (1.56.1) for rustler. The MSRV is restricted by the use of edition 2021 in rustler_bigint. With that, we can restrict the lints clippy emits to only those which can also be fixed for the MSRV.

Hello!

First of all, wanted to say this project is amazing, I'm a newbie at Rust and I was still able to write a nif and use it in Elixir!

While most of what I was set to code is working, there is one more thing I couldn't crack.

The nif I'm working on receives an Elixir map as an argument. The map can have different kinds of values (maps, lists, booleans, ints, floats, etc).

While decoding the Map as a Rust Struct, I'm having issues while decoding numbers. Since the map is dynamic, I don't know beforehand if the value I'm going to decode is an int or a float, and I haven't been able to make this work for both ints and floats at the same time.

This is the code I have:

if term.is_number() {
   let number_scalar: f64 = term.decode::<f64>().unwrap();
   ...
}
...

In order to call the right decoder, I need to specify the type but given I don't know the type, I can't do that. I checked rustler and there is no term.is_float or term.is_int which could help me out.

I imagine the possibility of doing something like:

if term.is_int() {
   let number_scalar: i32 = term.decode::<i32>().unwrap();
   ...
} else if term.is_float() {
  let number_scalar: f64 = term.decode::<f64>().unwrap();
}

Is this possible? if it's not, does anybody has any recommendations on how to handle this case?

This PR fixes #500 by adding a Rust typeErlOption<T> to the Rustler crate.

ErlOption<T> is a wrapper around Option<T>. It implements Rustler's Encoder and Decoder, and serializes None into undefined atom instead of nil. The undefined atom is commonly used in Erlang libraries to express the absence of a value.

For convenience, ErlOption<T> implements some traits from std, so that it will be easy to get a reference of enclosing Option<T> or convert from/to Option<T>. Here are the examples from its doc:

use rustler::ErlOption;

// Create new `ErlOption<i32>` values via convenient functions.
let _ = ErlOption::some(1); // Wraps `Some(1)`.
let _ = ErlOption::<i32>::none();

// Convert Option<i32> values to ErlOption<i32> values.
let _ = ErlOption::from(Some(2));
let _: ErlOption<_> = Some(3).into();
let _: ErlOption<i32> = None.into();

// Get a reference of enclosing Option<T> from an ErlOption<T>.
let _: &Option<i32> = ErlOption::some(4).as_ref();

// Get a mutable reference of enclosing Option<T> from an ErlOption<T>.
let _: &mut Option<i32> = ErlOption::some(5).as_mut();

// Convert an ErlOption<i32> value to an Option<i32> value.
let _: Option<i32> = ErlOption::some(6).into();

// Compare ErlOption<T> with Option<T>.
assert_eq!(ErlOption::some(7), Some(7));
assert!(ErlOption::some(8) > Some(7));

// Call Option<T>'s methods on an ErlOption<T> via Deref and DerefMut.
assert!(ErlOption::some(9).is_some());
assert_eq!(ErlOption::some(10).unwrap(), 10);
assert_eq!(ErlOption::some(12).map(|v| v + 1), ErlOption::some(13));

Hi,

First of all, Rustler is awesome, creating the NIF seems much simplified compared to C!

I was wondering about what would be the best practice for errors, in particular it would be nice to have errors using ?. I have put together a repo for it at https://github.com/KoviRobi/rustler_raise_error and I was wondering if there is an easier way to do it?

It's possible my whole use-case/assumptions are wrong, of course, and this isn't the right way to go about handling errors. What I wanted is an easy way to do errors that are semi user-understandable (not necessarily in normal English but a tech person should be able to figure it out). Here is what I got:

1. Using the {:ok, _}, {:error, _} paradigm

   iex(1)> NIF.getenv("FOO")
   {:error, "Variable not set: environment variable not found"}
   

   Note that this paradigm doesn't need the wrapper. I've just used one so that I can also reuse it for getenv!. But thinking about this, the whole thing wouldn't be so bad if we could reuse the function definition for the non-! version (currently it's impossible because the definition is hidden behind a structure).

2. Using the exceptions paradigm -- this also shows what advantage it might have over {:ok, _} = ... which is printing the arguments the function was called with.

   iex(2)> NIF.getenv!("FOO")
   ** (ErlangError) Erlang error: "Variable not set: environment variable not found"
       (rustler_raise_error 0.1.0) NIF.getenv!("FOO")
   iex(2)> {:ok, value} = NIF.getenv("FOO")
   ** (MatchError) no match of right hand side value: {:error, "Variable not set: environment variable not found"}
   

This also brought up the question, is there a way to have functions in Rustler that have ! in them? I tried doing

#[nif(name = "getenv!")]

but that didn't seem to work, it failed with

error: custom attribute panicked
  --> src/lib.rs:64:1
   |
64 | #[nif(name = "getenv!")]
   | ^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: message: `"getenv!"` is not a valid identifier

which seems like a bug? I've had a go at solving it in https://github.com/rusterlium/rustler/pull/505

There is as far as I know, no reason for the erlang function name to be an identifier.

To use, do

\#[nif(name = "foo!")]
fn foo_bang(...) -> ... {
    ...
}

First of all, thank you for creating Rustler! I really enjoy using it.

I have a Cargo.toml that looks something like this:

[package]
name = "name"

[lib]
name = "name"
path = "src/lib.rs"
crate-type = ["cdylib"]

[[bin]]
name = "name-bin"
path = "src/main.rs"
required-features = ["build-binary"]

I use the lib artifact in my Elixir code, and I use the bin artifact to debug the lib with some GUI stuff that's not needed in the lib artifact (prevents fetching and compiling unneeded dependencies).

Once it has successfully compiled, Rustler tries to copy all artifacts:

** (File.CopyError) could not copy from "/app/_build/prod/lib/xx/native/name/release/name-bin" to "priv/native/name-bin": no such file or directory
    (elixir 1.14.0) lib/file.ex:838: File.cp!/3
    (elixir 1.14.0) lib/enum.ex:975: Enum."-each/2-lists^foreach/1-0-"/2
    (rustler 0.26.0) lib/rustler/compiler.ex:44: Rustler.Compiler.compile_crate/2
    ...

This is not desired because I only need the lib, which has successfully compiled. Instead, my build failed because not every artifact was compiled.

Related Rustler code: https://github.com/rusterlium/rustler/blob/rustler-0.26.0/rustler_mix/lib/rustler/compiler.ex#L178 https://github.com/rusterlium/rustler/blob/rustler-0.26.0/rustler_mix/lib/rustler/compiler.ex#L197

My personal preference would go to a solution like this: Continue to try to copy all possible artifacts, but give a warning instead of halting the Rustler compile process when a specific artifact doesn't exist (but maybe require at least one artifact per package?). I'm also ok with a solution that allows people to exclude/include specific artifacts.