AnyId (p_-)

This library provides anyid::AnyId. a struct can be used as an identifier for HashMap keys, etc., while keeping the type information ambiguous.

Why is this necessary?

All data often has an identifier to identify it. Often it is tightly constrained by the type. (e.g, using the NewType pattern such as ProductId(uuid::Uuid) instead of just uuid::Uuid). However, when these data are lumped together and treated as just data in an integrated manner, such type restrictions seem a bit cumbersome. Therefore, we can solve this problem by providing a TraitObject that uses a Trait that is a collection of Traits that would be implemented at a minimum when used as an identifier. Note that this crate is intended to facilitate data handling at the application level and is not intended for ignore type processing such as (De)Serialize. Also, if you use this crate as an identifier for data, it can be very troublesome later on, since it only implements what is needed to handle the data in an organized manner.

Details

Inner structure

anyid::AnyId internally uses Trait, Identifier wrapped in Arc<T> as a trait-object.

pub struct AnyId(Arc<dyn Identifier>);

Trait-bound

Trait, Identifier, is automatically implemented for structures with several Trait implementations.

• Copy
  • Why is this required: When there is a scope that requires a 'static lifetime, such as in tokio::spawn, or when inserting data into a HashMap, etc., the data is usually duplicated, since it consumes values and can be used over and over again. In most cases, duplicated data is used. In addition, we thought that Copy would be more appropriate than Clone because the identifier should be “less resource-intensive to duplicate”.
• PartialEq/Eq
• Display/Debug
• Sync/Send
• Hash

Usage

construct

anyid::AnyId is provided new just like a general structure, argument requires an impl Identifier.

use anyid::AnyId;

fn main() {
    let str_id: &str = "abc123";
    let id = AnyId::new(str_id);
}

Also, If the default implementation conditions for Identifier are met, a From implementation is automatically provided.

use anyid::AnyId;

fn main() {
  let str_id: &str = "abc123";
  let id: AnyId = str_id.into();
}

Clone

anyid::AnyId itself does not provide Copy.
However, it implements Clone using Arc::clone as is.

impl Clone for AnyId {
  fn clone(&self) -> Self {
    Self(Arc::clone(&self.0))
  }
}

Therefore, cost of Clone is less.

Equal

Implementation of Eq/(PartialEq). is in Identifier.

fn eq(&self, other: &dyn Identifier) -> bool {
  let Some(other) = other.as_any().downcast_ref::<T>() else {
    return false;
  };

  self.eq(other)
}

It is quite simple, but it is important to note that this process does not use Result<T, E>. false is returned if the downcast fails.

license

This library is released under MIT license.
Bug reports and improvements are welcome ;D.