Derive Macro rustler::NifTaggedEnum
source · #[derive(NifTaggedEnum)]
{
// Attributes available to this derive:
#[rustler]
}
Expand description
Implementation of the NifTaggedEnum
macro that lets the user annotate an enum that will
generate elixir values when encoded. This can be used for any rust enums and will generate
three types of values based on the kind of the enum. For example from the test code:
ⓘ
#[derive(NifTaggedEnum)]
enum TaggedEnum {
Foo,
Bar(String),
Baz{ a: i32, b: i32 },
}
pub fn tagged_enum_echo<'a>(env: Env<'a>, args: &[Term<'a>]) -> NifResult<Term<'a>> {
let tagged_enum: TaggedEnum = args[0].decode()?;
Ok(tagged_enum.encode(env))
}
This can be used from elixir in the following manner.
test "tagged enum transcoder" do
assert :foo == RustlerTest.tagged_enum_echo(:foo)
assert {:bar, "Hello"} == RustlerTest.tagged_enum_echo(:bar, "Hello")
assert {:baz, %{a: 33, b: 21}} == RustlerTest.tagged_enum_echo({:baz, %{a: 33, b: 21}})
end