statum-core

statum-core contains the small stable runtime surface shared by the Statum workspace.

Public surface:

• statum_core::Error
• statum_core::Result<T>
• StateMarker, UnitState, DataState
• CanTransitionTo, CanTransitionWith, CanTransitionMap
• statum_core::projection
• optional introspection and presentation descriptors behind the introspection feature, such as MachineGraph, MachineDescriptor, StateDescriptor, TransitionDescriptor, RecordedTransition, and the inventory/presentation helpers used by generated machine metadata

Install

[dependencies]
statum-core = "0.8.10"

Example

fn ensure_ready(ready: bool) -> statum_core::Result<()> {
    if ready {
        Ok(())
    } else {
        Err(statum_core::Error::InvalidState)
    }
}

Projection helpers are available for event-log style rebuilds:

use statum_core::projection::{ProjectionReducer, reduce_one};

struct Sum;

impl ProjectionReducer<u64> for Sum {
    type Projection = u64;
    type Error = core::convert::Infallible;

    fn seed(&self, event: &u64) -> Result<Self::Projection, Self::Error> {
        Ok(*event)
    }

    fn apply(&self, projection: &mut Self::Projection, event: &u64) -> Result<(), Self::Error> {
        *projection += event;
        Ok(())
    }
}

let total = reduce_one(vec![1_u64, 2, 3], &Sum).unwrap();
assert_eq!(total, 6);

Docs

• API docs: https://docs.rs/statum-core
• Repository: https://github.com/eboody/statum