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pub mod alphabet; | ||
// pub mod mealy; | ||
pub mod mealy; | ||
pub mod moore; | ||
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pub(crate) mod util; |
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use std::ops::{Index, IndexMut}; | ||
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use state::{State, StateId}; | ||
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use crate::alphabet::Alphabet; | ||
use crate::util::arena::Arena; | ||
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pub mod state; | ||
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// #[cfg(feature = "serde")] | ||
// mod serde; | ||
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/// Mealy machine is a tuple $(Q, q_0, \Sigma, \Lambda, \delta, \omega)$, where | ||
/// - $Q$ is a set of states, | ||
/// - $q_0$ is an initial (start) state, | ||
/// - $\Sigma$ is an input alphabet, | ||
/// - $\Lambda$ is an output alphabet, | ||
/// - $\delta : Q \times \Sigma \to Q$ is a transition function, | ||
/// - $\omega : Q \times \Sigma \to \Lambda$ is an output function. | ||
#[derive(Debug)] | ||
pub struct Mealy<I: Alphabet, O: Alphabet> { | ||
states: Arena<State<I, O>>, | ||
} | ||
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impl<I: Alphabet, O: Alphabet> Mealy<I, O> { | ||
pub fn new() -> Self { | ||
Self { | ||
states: Arena::new(), | ||
} | ||
} | ||
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pub fn add_state(&mut self) -> StateId { | ||
self.states.alloc_with_id(|id| State::new(id)) | ||
} | ||
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pub fn add_transition(&mut self, from: StateId, input: I, to: StateId, output: O) { | ||
self.state_mut(from).add_transition(input, to, output); | ||
} | ||
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pub fn state(&self, index: StateId) -> &State<I, O> { | ||
&self.states[index] | ||
} | ||
pub fn state_mut(&mut self, index: StateId) -> &mut State<I, O> { | ||
&mut self.states[index] | ||
} | ||
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pub fn num_states(&self) -> usize { | ||
self.states.len() | ||
} | ||
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pub fn num_transitions(&self) -> usize { | ||
self.states().map(|state| state.num_transitions()).sum() | ||
} | ||
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pub fn states(&self) -> impl Iterator<Item = &State<I, O>> { | ||
self.states.iter() | ||
} | ||
pub fn states_mut(&mut self) -> impl Iterator<Item = &mut State<I, O>> { | ||
self.states.iter_mut() | ||
} | ||
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pub fn transitions(&self) -> impl Iterator<Item = (&State<I, O>, I, &State<I, O>, O)> + '_ { | ||
self.states().flat_map(move |state| { | ||
state | ||
.transitions() | ||
.map(move |(input, to, output)| (state, input, self.state(to), output)) | ||
}) | ||
} | ||
} | ||
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impl<I: Alphabet, O: Alphabet> Default for Mealy<I, O> { | ||
fn default() -> Self { | ||
Self::new() | ||
} | ||
} | ||
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impl<I: Alphabet, O: Alphabet> Index<StateId> for Mealy<I, O> { | ||
type Output = State<I, O>; | ||
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fn index(&self, index: StateId) -> &Self::Output { | ||
self.state(index) | ||
} | ||
} | ||
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impl<I: Alphabet, O: Alphabet> IndexMut<StateId> for Mealy<I, O> { | ||
fn index_mut(&mut self, index: StateId) -> &mut Self::Output { | ||
self.state_mut(index) | ||
} | ||
} | ||
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impl<I: Alphabet, O: Alphabet> Mealy<I, O> { | ||
pub fn next(&self, current_state: StateId, input: I) -> Option<(StateId, O)> { | ||
self.state(current_state).next(input) | ||
} | ||
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pub fn run<'a, Inputs>(&'a self, inputs: Inputs) -> impl Iterator<Item = (I, StateId, O)> + '_ | ||
where | ||
Inputs: IntoIterator<Item = I>, | ||
<Inputs as IntoIterator>::IntoIter: 'a, | ||
{ | ||
let mut current_state = 0; | ||
inputs.into_iter().map(move |input: I| { | ||
let (next_state, output) = self.next(current_state, input).unwrap(); | ||
current_state = next_state; | ||
(input, current_state, output) | ||
}) | ||
} | ||
} | ||
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#[cfg(test)] | ||
mod tests { | ||
use super::*; | ||
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#[test] | ||
fn test_mealy_run() { | ||
let mut fsm = Mealy::new(); | ||
let q0 = fsm.add_state(); | ||
let p0 = fsm.add_state(); | ||
let p1 = fsm.add_state(); | ||
fsm.add_transition(q0, 0, p0, false); | ||
fsm.add_transition(q0, 1, p1, false); | ||
fsm.add_transition(p0, 0, p0, true); | ||
fsm.add_transition(p0, 1, p1, false); | ||
fsm.add_transition(p1, 0, p0, false); | ||
fsm.add_transition(p1, 1, p1, true); | ||
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let inputs = vec![0,1,1,0,0]; | ||
println!("Running Moore machine on {:?}", inputs); | ||
let mut current_state = 0; | ||
let mut outputs = Vec::new(); | ||
println!("initial state {}", current_state); | ||
for (input, new_state, output) in fsm.run(inputs) { | ||
println!( | ||
"state {}, input {}, new_state {}, output {}", | ||
current_state, input, new_state, output | ||
); | ||
outputs.push(output); | ||
current_state = new_state; | ||
} | ||
assert_eq!(outputs, vec![false, false, true, false, true]); | ||
} | ||
} |
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use std::collections::HashMap; | ||
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use crate::alphabet::Alphabet; | ||
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pub type StateId = usize; | ||
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#[derive(Debug)] | ||
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))] | ||
pub struct State<I: Alphabet, O: Alphabet> { | ||
pub id: StateId, | ||
transitions: HashMap<I, (StateId, O)>, | ||
} | ||
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impl<I: Alphabet, O: Alphabet> State<I, O> { | ||
pub fn new(id: StateId) -> Self { | ||
Self { | ||
id, | ||
transitions: HashMap::new(), | ||
} | ||
} | ||
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pub fn add_transition(&mut self, input: I, to: StateId, output: O) { | ||
self.transitions.insert(input, (to, output)); | ||
} | ||
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pub fn num_transitions(&self) -> usize { | ||
self.transitions.len() | ||
} | ||
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pub fn transitions(&self) -> impl Iterator<Item = (I, StateId, O)> + '_ { | ||
self.transitions | ||
.iter() | ||
.map(|(&symbol, &(to, output))| (symbol, to, output)) | ||
} | ||
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pub fn next(&self, input: I) -> Option<(StateId, O)> { | ||
self.transitions.get(&input).copied() | ||
} | ||
} |