token_cell/lib.rs
1//! This library provides an alternative to [`ghost-cell`](https://crates.io/crates/ghost-cell) which uses concrete types instead of lifetimes for branding.
2//!
3//! This allows a more convenient usage, where cells and tokens can be constructed independently, with the same compile-time guarantees as [`ghost-cell`](https://crates.io/crates/ghost-cell). The trade-off for this arguably more convenient usage and arguably easier to understand branding method is that tokens, while zero-sized if made correctly, must be guaranteed to be constructable only if no other instance exists.
4//!
5//! To this end, this crate provides the [`generate_token`] macro, which will create a ZST which can only be constructed using [`TokenTrait::aquire`], which is generated to guarantee no other token exists before returning the token. This is done by checking a static `AtomicBool` flag, which is the only runtime cost of these tokens.
6#![cfg_attr(not(features = "std"), no_std)]
7pub use paste::paste;
8#[cfg(features = "std")]
9mod std {
10 use crate::macros::{IdMismatch, SingletonUnavailable};
11 extern crate std;
12 impl std::error::Error for IdMismatch {}
13 impl std::error::Error for SingletonUnavailable {}
14}
15pub mod prelude {
16 pub use crate::core::{TokenCell, TokenCellTrait, TokenTrait};
17}
18pub use crate::macros::token;
19pub mod core;
20pub mod ghost;
21pub mod macros;
22pub mod monads;
23
24runtime_token!(pub RuntimeToken);