Regular-Expresso Changeset - 6f7aa78a47f7

Changeset - 6f7aa78a47f7

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Laman - 10 months ago 2024-06-11 22:33:48

added a proper START constant

1 file changed with 6 insertions and 4 deletions:

src/main.rs

6

4

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src/main.rs

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 use std::collections::{HashMap, HashSet};
 const START: usize = usize::MAX;
 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
+}
@@ @@ -121,26 +123,26 @@ fn parse(pattern: &String, offset: usize @@
 	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}));
 				let token = res.pop().unwrap();
 				res.push(Box::new(Asterisk{content: token}));
 				i += 1;
+			}
 			c => {
 				res.push(Box::new(Symbol{position: i+offset, value: c}));
 				i += 1;
+			}
+		}
+	}
 	return Chain{content: res};
+}
@@ @@ -148,47 +150,47 @@ struct Regexp { @@
 	rules: HashMap<(usize, char), HashSet<usize>>,
 	end_states: HashSet<usize>
+}
 impl Regexp {
 	fn new(pattern: &String) -> Regexp {
 		let r = parse(pattern, 0);
 		let pattern_chars = Vec::from_iter(pattern.chars());
 		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);
+			let key = (START, c);
 			match rules.get_mut(&key) {
 				Some(set) => {set.insert(i);},
 				None => {rules.insert(key, HashSet::from([i]));}
 			};
+		}
 		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 {
-		let mut multistate = HashSet::from([99]);
+		let mut multistate = HashSet::from([START]);
 		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;

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