Crate yasm

YASM (Yet Another State Machine)

A modern, efficient deterministic state machine library designed for Rust 2024 edition.

Features

• Deterministic State Machine: Each state+input combination has at most one possible next state
• Type Safety: Leverage Rust’s type system to ensure state machine correctness
• Macro Support: Use declarative macros to quickly define state machines
• History Tracking: Automatically maintain state transition history for debugging and analysis
• Query Functions: Rich state machine analysis capabilities
• Documentation Generation: Automatically generate Mermaid diagrams and transition tables
• Serde Support: Optional serialization and deserialization support

Basic Usage

use yasm::*;

// Define state machine
define_state_machine! {
    name: TrafficLight,
    states: { Red, Yellow, Green },
    inputs: { Timer, Emergency },
    initial: Red,
    transitions: {
        Red + Timer => Green,
        Green + Timer => Yellow,
        Yellow + Timer => Red,
        Red + Emergency => Yellow,
        Green + Emergency => Red,
        Yellow + Emergency => Red
    }
}

// Create state machine instance
let mut traffic_light = StateMachineInstance::<TrafficLight>::new();

// Execute state transition
traffic_light.transition(Input::Timer).unwrap();
assert_eq!(*traffic_light.current_state(), State::Green);

Module Structure

• core: Core trait and type definitions
• instance: State machine instance implementation
• query: State machine query and analysis functionality
• doc: Documentation generation functionality
• macros: Macro definitions

Re-exports

pub use callbacks::CallbackRegistry;

pub use core::StateMachine;

pub use doc::StateMachineDoc;

pub use instance::StateMachineInstance;

pub use query::StateMachineQuery;

Modules

callbacks

core

doc

instance

macros

query

Macros

define_state_machine

Macro for defining deterministic state machines - non-serde version

Constants

DEFAULT_MAX_HISTORY_SIZE

Default maximum history size