Regular-Expresso Changeset

Changeset - 4f7b6352013d

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Laman - 10 months ago 2024-06-23 22:48:03

added the automaton normalization

4 files changed with 55 insertions and 14 deletions:

regexp.py

src/main.rs

src/regexp.rs

tests/test_regexp.rs

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regexp.py

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 from abc import abstractmethod
 from collections import deque
 class ParsingError(Exception):
@@ @@ -283,7 +284,7 @@ class RegexpDFA: @@
 		return cls(rules, end_states)
 	def match(self, s):
-		st = (-1,)
+		st = 0
 		for c in s:
 			key = (st, c)
@@ @@ -300,6 +301,24 @@ class RegexpDFA: @@
 		return RegexpDFA(rules, end_states)
 	def normalize(self):
 		index = {(-1,): 0}
 		queue = deque([(-1,)])
 		while queue:
 			state = queue.popleft()
 			edges = [((st, c), t) for ((st, c), t) in self.rules.items() if st == state]
 			edges.sort()
 			for ((st, c), t) in edges:
 				if t not in index:
 					index[t] = len(index)
 					queue.append(t)
 		rules = dict(((index[st], c), index[t]) for ((st, c), t) in self.rules.items())
 		end_states = {index[st] for st in self.end_states}
 		return RegexpDFA(rules, end_states)
 	def _find_equivalent_states(self):
 		state_set = [(-2,), (-1,)] + sorted(set(self.rules.values()))
 		alphabet = {c for (st, c) in self.rules.keys()}
@@ @@ -340,10 +359,10 @@ class RegexpDFA: @@
 if __name__ == "__main__":
 	tests = ["", "a", "ab", "aabb", "abab", "abcd", "abcbcdbcd"]
 	for pattern in ["a(b|c)", "a*b*", "(ab)*", "a((bc)*d)*"]:
+	for pattern in ["a(b|c)", "a*b*", "(ab)*", "a((bc)*d)*", "(a|b)*a(a|b)(a|b)(a|b)"]:
 		print("#", pattern)
 		try:
 			r = RegexpDFA.create(pattern).reduce()
+			r = RegexpDFA.create(pattern).reduce().normalize()
 		except ParsingError as e:
 			print("Failed to parse the regexp:")
 			print(e)

src/main.rs

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@@ @@ -2,10 +2,10 @@ use regexp::Regexp; @@
 fn main() {
 	let tests = ["", "a", "ab", "aabb", "abab", "abcd", "abcbcdbcd"];
 	for pattern in ["a(b|c)", "a*b*", "(ab)*", "a((bc)*d)*"] {
+	for pattern in ["a(b|c)", "a*b*", "(ab)*", "a((bc)*d)*", "(a|b)*a(a|b)(a|b)(a|b)"] {
 		println!("# {pattern}");
 		let r = match Regexp::new(&pattern.to_string()) {
 			Ok(r1) => r1.determinize().reduce(),
+			Ok(r1) => r1.determinize().reduce().normalize(),
 			Err(e) => {
 				println!("{e}");
 				continue;

src/regexp.rs

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 use std::collections::{HashMap, HashSet};
+use std::collections::{HashMap, HashSet, VecDeque};
 mod token;
 pub use token::ParsingError;
@@ @@ -151,6 +151,28 @@ impl RegexpDFA { @@
 		return self.collapse_states(equivalents);
+	}
 	pub fn normalize(&self) -> RegexpDFA {
 		let mut index = HashMap::from([(START as u64, START as u64)]);
 		let mut queue = VecDeque::from([START as u64]);
 		while !queue.is_empty() {
 			let state = queue.pop_front().unwrap();
 			let mut edges: Vec<((u64, char), u64)> = self.rules.iter().filter(|((st, c), t)| *st == state).map(|((st, c), t)| ((*st, *c), *t)).collect();
 			edges.sort();
 			for ((_st, _c), t) in edges {
 				if !index.contains_key(&t) {
 					index.insert(t, index.len() as u64);
 					queue.push_back(t);
+				}
+			}
+		}
 		let rules = self.rules.iter().map(|((st, c), t)| ((index[st as &u64], *c), index[t as &u64])).collect();
 		let end_states = self.end_states.iter().map(|st| index[st]).collect();
 		return RegexpDFA{rules, end_states};
+	}
 	fn find_equivalent_states(&self) -> Vec<(u64, u64)> {
 		let state_set: HashSet<u64> = HashSet::from_iter(self.rules.values().copied());
 		let mut state_vec: Vec<u64> = Vec::from_iter(state_set.into_iter());

tests/test_regexp.rs

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@@ @@ -11,7 +11,7 @@ fn test_eval_basic_nfa() { @@
 #[test]
 fn test_eval_basic_dfa() {
 	let r = Regexp::new(&String::from("abc")).unwrap().determinize().reduce();
+	let r = Regexp::new(&String::from("abc")).unwrap().determinize().reduce().normalize();
 	assert!(r.eval(String::from("abc")));
 	assert!(!r.eval(String::from("ab")));
 	assert!(!r.eval(String::from("abcd")));
@@ @@ -27,9 +27,9 @@ fn test_eval_empty_nfa() { @@
 #[test]
 fn test_eval_empty_dfa() {
 	assert!(Regexp::new(&String::from("a*")).unwrap().determinize().reduce().eval(String::from("")));
 	assert!(Regexp::new(&String::from("")).unwrap().determinize().reduce().eval(String::from("")));
 	assert!(!Regexp::new(&String::from("")).unwrap().determinize().reduce().eval(String::from("a")));
 	assert!(Regexp::new(&String::from("a*")).unwrap().determinize().reduce().normalize().eval(String::from("")));
 	assert!(Regexp::new(&String::from("")).unwrap().determinize().reduce().normalize().eval(String::from("")));
 	assert!(!Regexp::new(&String::from("")).unwrap().determinize().reduce().normalize().eval(String::from("a")));
+}
 #[test]
@@ @@ -43,7 +43,7 @@ fn test_eval_asterisk_nfa() { @@
 #[test]
 fn test_eval_asterisk_dfa() {
 	let r = Regexp::new(&String::from("a*b*")).unwrap().determinize().reduce();
+	let r = Regexp::new(&String::from("a*b*")).unwrap().determinize().normalize().reduce();
 	assert!(r.eval(String::from("a")));
 	assert!(r.eval(String::from("ab")));
 	assert!(r.eval(String::from("aabb")));
@@ @@ -62,7 +62,7 @@ fn test_eval_alternative_nfa() { @@
 #[test]
 fn test_eval_alternative_dfa() {
 	let r = Regexp::new(&String::from("a|b|c")).unwrap().determinize().reduce();
+	let r = Regexp::new(&String::from("a|b|c")).unwrap().determinize().reduce().normalize();
 	assert!(r.eval(String::from("a")));
 	assert!(r.eval(String::from("b")));
 	assert!(r.eval(String::from("c")));
@@ @@ -85,12 +85,12 @@ fn test_eval_lambda_nfa() { @@
 #[test]
 fn test_eval_lambda_dfa() {
 	let r = Regexp::new(&String::from("a_")).unwrap().determinize().reduce();
+	let r = Regexp::new(&String::from("a_")).unwrap().determinize().reduce().normalize();
 	assert!(r.eval(String::from("a")));
 	assert!(!r.eval(String::from("")));
 	assert!(!r.eval(String::from("ab")));
 	let r = Regexp::new(&String::from("a|_")).unwrap().determinize().reduce();
+	let r = Regexp::new(&String::from("a|_")).unwrap().determinize().reduce().normalize();
 	assert!(r.eval(String::from("a")));
 	assert!(r.eval(String::from("")));
 	assert!(!r.eval(String::from("b")));

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