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.

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
  • Because most of the time, keys are used in K/V arrays. In addition, identifiers are desirable because they should be less costly 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.