Check if Term is float about rustler HOT 5 CLOSED

Is there any particular reason, why Term::get_type() is implemented using the various is_* methods

enif_term_type was introduced with OTP 22.0, so it was not around when get_type() was implemented.

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• You should not use unwrap in "production" code. It will not crash your code but only because Rustler explicitly handles panics
• Instead, you can use if let or match (or unwrap_or, there are plenty of options) to first try to decode as integer and, if that fails, decode as float instead
• @ all: Is there any particular reason, why Term::get_type() is implemented using the various is_* methods (which map to enif_is_*)? Erlang's built in enif_term_type can actually distinguish floats and integers, changing the behaviour of get_type in this way now would be a breaking change, though.

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@filmor Thanks so much for your reply! will implement this update!

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Then I'll add it. @rusterlium/core do you think it's fine to break API here by adjusting the enum or should I add a new function?

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https://github.com/orgs/rusterlium/teams/core do you think it's fine to break API here by adjusting the enum or should I add a new function?

I'd tend to deprecate this function and schedule for removal in 1.0, and add a new function instead.

Maybe impl From<Term> for TermType would be the way to go here. That allows us to keep the deprecated function around and avoid thinking of a new name. Alternatively, Term::as_type should fit as well, as this is a cheap function.

I imagine the possibility of doing something like:

rustler_codegen can help you here by deriving that decoder above automatically. NifUntaggedEnum implements Decode and Encode for an enum. Example:

#[derive(NifUntaggedEnum)]
enum MyEnum {
  Float(f64),
  Integer(i64)
}

#[rustler::nif]
fn my_nif(my_enum: MyEnum) -> MyEnum {
  my_enum // this is a variant of MyEnum, which was already decoded and which will be encoded after it was returned
}

(Disclaimer: I did not compile the code above :))

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