Regular-Expresso Changeset

Changeset - 1a11f659e7b5

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Laman - 11 months ago 2024-06-11 22:29:10

the prototype rewritten to Rust

1 file changed with 177 insertions and 114 deletions:

src/main.rs

177

114

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src/main.rs

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 use std::collections::{HashMap, HashSet};
 trait Token {
 	fn is_skippable(&self) -> bool {false}
 	fn list_first(&self) -> Vec<usize>;
 	fn list_last(&self) -> Vec<usize>;
 	fn list_neighbours(&self) -> Vec<(usize, usize)>;
+}
 struct Symbol {
 	position: usize,
 	value: char
+}
 struct Asterisk {
 	content: Box<dyn Token>
+}
 struct Chain {
 	content: Vec<Box<dyn Token>>
+}
 impl Token for Symbol {
 	fn list_first(&self) -> Vec<usize> {
 		return vec![self.position];
+	}
 	fn list_last(&self) -> Vec<usize> {
 		return vec![self.position];
+	}
 	fn list_neighbours(&self) -> Vec<(usize, usize)> {
 		return vec![];
+	}
+}
 impl Token for Asterisk {
 	fn is_skippable(&self) -> bool {true}
 	fn list_first(&self) -> Vec<usize> {
 		return self.content.list_first();
+	}
 	fn list_last(&self) -> Vec<usize> {
 		return self.content.list_last();
+	}
 	fn list_neighbours(&self) -> Vec<(usize, usize)> {
 		let mut res = self.content.list_neighbours();
 		for x in self.list_last() {
 			for y in self.list_first() {
 				res.push((x, y));
+			}
+		}
 		return res;
+	}
+}
 impl Token for Chain {
 	fn list_first(&self) -> Vec<usize> {
 		let mut res = Vec::new();
 		for token in self.content.iter() {
 			res.append(&mut token.list_first());
 			if !token.is_skippable() {break;}
+		}
 		return res;
+	}
 	fn list_last(&self) -> Vec<usize> {
 		let mut res = Vec::new();
 		for token in self.content.iter().rev() {
 			res.append(&mut token.list_last());
 			if !token.is_skippable() {break;}
+		}
 		return res;
+	}
 	fn list_neighbours(&self) -> Vec<(usize, usize)> {
 		let mut res = Vec::new();
 		let mut previous: Vec<&Box<dyn Token>> = Vec::new();
 		for token in self.content.iter() {
 			for t in previous.iter() {
 				for x in t.list_last() {
 					for y in token.list_first() {
 						res.push((x, y));
+					}
+				}
+			}
 			res.append(&mut token.list_neighbours());
 			if token.is_skippable() {
 				previous.push(token);
 			} else {
 				previous = vec![token];
+			}
+		}
 		return res;
+	}
+}
 fn find_closing_parenthesis(s: &String) -> Option<usize> {
 	let chars: Vec<char> = s.chars().collect();
 	let mut counter = 0;
 	for (i, c) in chars.iter().enumerate() {
 		if *c == '(' {counter += 1;}
 		else if *c == ')' {counter -= 1;}
 		if counter == 0 {return Some(i);}
+	}
 	return None;
+}
 fn parse(pattern: &String, offset: usize) -> Chain {
 	let chars: Vec<char> = pattern.chars().collect();
 	let mut res: Vec<Box<dyn Token>> = Vec::new();
 	let mut i = 0;
 	while i < pattern.len() {
 		let c = chars[i];
 		match c {
 			'(' => {
 				let j = find_closing_parenthesis(&pattern[i..].to_string()).unwrap() + i;
 				let inner_content = parse(&pattern[i+1..j].to_string(), offset+i+1);
 				res.push(Box::new(inner_content));
 				i = j+1;
+			}
 			'*' => {
 				let segment = res.pop().unwrap();
 				res.push(Box::new(Asterisk{content: segment}));
 				i += 1;
+			}
 			c => {
 				res.push(Box::new(Symbol{position: i+offset, value: c}));
 				i += 1;
+			}
+		}
+	}
 	return Chain{content: res};
+}
 struct Regexp {
 	rules: HashMap<(usize, char), HashSet<usize>>,
 	end_states: HashSet<usize>
+}
 impl Regexp {
 	pub fn new(pattern: String) -> Self {
 		println!("> {pattern}");
 	fn new(pattern: &String) -> Regexp {
 		let r = parse(pattern, 0);
 		let pattern_chars = Vec::from_iter(pattern.chars());
 		let mut star = false;
 		let mut plus = false;
 		let n = pattern.len();
 		let mut states = vec![HashSet::from([n])];
 		let mut end_states = HashSet::new();
 		let mut rules = HashMap::new();
 		for i in 0..n {
 			let j = n-i-1;
 			let c = pattern_chars[j];
 			let k = states.len()-1;
 			if c == '*' {
 				star = true;
 				continue;
+			}
 			if c == '+' {
 				plus = true;
 				continue;
+			}
 			if star {
 				states[k].insert(j);
 				println!("{j}: {:?}", states[k]);
 				Regexp::update_rule(&mut rules, j, &pattern_chars, &states[k]);
 				if states[k].contains(&n) {end_states.insert(j);}
 				star = false;
+			}
 			else if plus {
 				states[k].insert(j);
 				println!("{j}: {:?}", states[k]);
 				Regexp::update_rule(&mut rules, j, &pattern_chars, &states[k]);
 				if states[k].contains(&n) {end_states.insert(j);}
 				states.push(HashSet::from([j]));
 				plus = false;
+			}
 			else {
 				println!("{j}: {:?}", states[k]);
 				Regexp::update_rule(&mut rules, j, &pattern_chars, &states[k]);
 				if states[k].contains(&n) {end_states.insert(j);}
 				states.push(HashSet::from([j]));
+			}
 			if j == 0 {
 				let m = states.len()-1;
 				println!("99: {:?} (start)", states[m]);
 				Regexp::update_rule(&mut rules, 99, &pattern_chars, &states[m]);
 				if states[m].contains(&n) {end_states.insert(j);}
+			}
 		let mut rules: HashMap<(usize, char), HashSet<usize>> = HashMap::new();
 		for i in r.list_first() {
 			let c = pattern_chars[i];
 			let key = (99, c);
 			match rules.get_mut(&key) {
 				Some(set) => {set.insert(i);},
 				None => {rules.insert(key, HashSet::from([i]));}
 			};
+		}
 		println!("{rules:?}");
 		return Regexp {rules, end_states};
 		for (i, j) in r.list_neighbours() {
 			let c = pattern_chars[j];
 			let key = (i, c);
 			match rules.get_mut(&key) {
 				Some(set) => {set.insert(j);},
 				None => {rules.insert(key, HashSet::from([j]));}
 			};
+		}
 		let end_states = HashSet::from_iter(r.list_last().into_iter());
 		return Regexp{rules, end_states};
+	}
 	pub fn eval(self, s: String) -> bool {
+	pub fn eval(&self, s: String) -> bool {
 		let mut multistate = HashSet::from([99]);
 		for c in s.chars() {
 			let mut new_multistate = HashSet::new();
 			for state in multistate {
 				if let Some(x) = self.rules.get(&(state, c)) {
 					new_multistate = new_multistate.union(&x).map(|&y| y).collect();
 				} else if let Some(x) = self.rules.get(&(state, '.')) {
 					new_multistate = new_multistate.union(&x).map(|&y| y).collect();
+				}
+			}
 			multistate = new_multistate;
+		}
 		return multistate.iter().any(|x| self.end_states.contains(x));
+	}
 	fn update_rule(rules: &mut HashMap<(usize, char), HashSet<usize>>, pos: usize, pattern: &Vec<char>, values: &HashSet<usize>) {
 		let n = pattern.len();
 		for &target in values.iter() {
 			println!("pos: {pos}, target: {target}");
 			if target == n {continue;}
 			let c = pattern[target];
 			let key = (pos, c);
 			if !rules.contains_key(&key) {rules.insert(key, HashSet::new());}
 			match rules.get_mut(&key) {
 				Some(set) => {set.insert(target);},
 				None => {rules.insert(key, HashSet::from([target]));}
 			};
+		}
+	}
 	fn find_previous_letter(s: &String, k: usize) -> Option<usize> {
 		return s[..k].rfind(char::is_alphanumeric);
+	}
 	fn find_next_letter(s: &String, k: usize) -> Option<usize> {
 		return s[k+1..].find(char::is_alphanumeric);
+	}
 	fn find_opening_parenthesis(s: &String, k: usize) -> Option<usize> {
 		let chars: Vec<char> = s.chars().collect();
 		let mut i = k;
 		let mut counter = 1;
 		while counter > 0 {
 			match chars[i] {
 				'(' => counter -= 1,
 				')' => counter += 1,
 				_ => {}
+			}
 			match i.checked_sub(1) {
 				Some(x) => i = x,
 				None => return None
+			}
+		}
 		return Some(i);
+	}
+}
 struct Solution {}
 impl Solution {
 	pub fn is_match(s: String, p: String) -> bool {
 		let regexp = Regexp::new(p);
 		return regexp.eval(s);
+	}
+}
 fn main() {
 	// println!("{}\n", Solution::is_match(String::from("aa"), String::from("a")));
 	// println!("{}\n", Solution::is_match(String::from("aa"), String::from("a*")));
 	// println!("{}\n", Solution::is_match(String::from("ab"), String::from(".*")));
 	// println!("{}\n", Solution::is_match(String::from("aab"), String::from("a*ab")));
 	// println!("{}\n", Solution::is_match(String::from("aab"), String::from("a*b*")));
 	println!("{}\n", Solution::is_match(String::from("a"), String::from("a+")));
 	println!("{}\n", Solution::is_match(String::from("aa"), String::from("a+")));
 	println!("{}\n", Solution::is_match(String::from(""), String::from("a+")));
 	println!("{}\n", Solution::is_match(String::from("bb"), String::from("ba+b")));
 	println!("{}\n", Solution::is_match(String::from("baaaaab"), String::from("ba+b")));
 	let tests = ["a", "ab", "aabb", "abab", "abcd", "abcbcdbcd"];
 	for pattern in ["a*b*", "(ab)*", "a((bc)*d)*"] {
 		println!("# {pattern}");
 		let r = Regexp::new(&pattern.to_string());
 		for &t in tests.iter() {
 			println!("{t} {}", r.eval(t.to_string()));
+		}
 		println!();
+	}
+}

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