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use rand::Rng;
use crate::grammar::Rule;
use super::{
RuleSelector,
ExpansionLogger
};
pub struct UniformRandomRuleSelector;
impl Default for UniformRandomRuleSelector {
fn default() -> Self {
Self::new()
}
}
impl<Nt, T> RuleSelector<Nt, T> for UniformRandomRuleSelector {
fn select_matching_rule<'a>(&self, matching_rules: &[&'a Rule<Nt, T>]) -> Option<&'a Rule<Nt, T>> {
if matching_rules.is_empty() {
None
} else {
let selected_rule_idx = rand::thread_rng().gen_range(0, matching_rules.len());
Some(matching_rules[selected_rule_idx])
}
}
}
impl UniformRandomRuleSelector {
pub fn new() -> Self {
Self
}
}
pub struct NullExpansionLogger;
impl<Nt, T> ExpansionLogger<Nt, T> for NullExpansionLogger {
}