3dbea91a63
Also, remove seemingly-unused generate_dummy method to enable this instance. Also, add an adapter that creates an Iterator from a Generator.
97 lines
2.5 KiB
Rust
97 lines
2.5 KiB
Rust
//! Gramatron generator
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use alloc::{string::String, vec::Vec};
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use core::marker::PhantomData;
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use serde::{Deserialize, Serialize};
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use crate::{
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bolts::rands::Rand,
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generators::Generator,
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inputs::{GramatronInput, Terminal},
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state::HasRand,
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Error,
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};
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/// A trigger
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#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
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pub struct Trigger {
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/// the destination
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pub dest: usize,
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/// the term
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pub term: String,
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}
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/// The [`Automaton`]
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#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
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pub struct Automaton {
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/// final state
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pub final_state: usize,
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/// init state
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pub init_state: usize,
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/// pda of [`Trigger`]s
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pub pda: Vec<Vec<Trigger>>,
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}
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#[derive(Clone, Debug)]
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/// Generates random inputs from a grammar automaton
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pub struct GramatronGenerator<'a, S>
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where
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S: HasRand,
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{
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automaton: &'a Automaton,
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phantom: PhantomData<S>,
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}
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impl<'a, S> Generator<GramatronInput, S> for GramatronGenerator<'a, S>
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where
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S: HasRand,
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{
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fn generate(&mut self, state: &mut S) -> Result<GramatronInput, Error> {
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let mut input = GramatronInput::new(vec![]);
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self.append_generated_terminals(&mut input, state);
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Ok(input)
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}
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}
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impl<'a, S> GramatronGenerator<'a, S>
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where
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S: HasRand,
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{
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/// Returns a new [`GramatronGenerator`]
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#[must_use]
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pub fn new(automaton: &'a Automaton) -> Self {
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Self {
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automaton,
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phantom: PhantomData,
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}
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}
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/// Append the generated terminals
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pub fn append_generated_terminals(&self, input: &mut GramatronInput, state: &mut S) -> usize {
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let mut counter = 0;
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let final_state = self.automaton.final_state;
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let mut current_state =
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input
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.terminals()
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.last()
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.map_or(self.automaton.init_state, |last| {
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let triggers = &self.automaton.pda[last.state];
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let idx = state.rand_mut().below(triggers.len() as u64) as usize;
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triggers[idx].dest
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});
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while current_state != final_state {
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let triggers = &self.automaton.pda[current_state];
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let idx = state.rand_mut().below(triggers.len() as u64) as usize;
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let trigger = &triggers[idx];
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input
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.terminals_mut()
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.push(Terminal::new(current_state, idx, trigger.term.clone()));
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current_state = trigger.dest;
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counter += 1;
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}
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counter
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}
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}
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