diff --git a/src/main.rs b/src/regexp.rs
copy from src/main.rs
copy to src/regexp.rs
--- a/src/main.rs
+++ b/src/regexp.rs
@@ -1,186 +1,10 @@
 use std::collections::{HashMap, HashSet};
 
+mod token;
+use token::{Token, parse};
+
 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
-}
-
-struct Asterisk {
-	content: Box<dyn Token>
-}
-
-struct Plus {
-	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 Plus {
-	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 is_skippable(&self) -> bool {
-		return self.content.iter().all(|x| x.is_skippable());
-	}
-
-	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 token = res.pop().unwrap();
-				res.push(Box::new(Asterisk{content: token}));
-				i += 1;
-			}
-			'+' => {
-				let token = res.pop().unwrap();
-				res.push(Box::new(Plus{content: token}));
-				i += 1;
-			}
-			c => {
-				res.push(Box::new(Symbol{position: i+offset, value: c}));
-				i += 1;
-			}
-		}
-	}
-
-	return Chain{content: res};
-}
-
 fn encode_set(set: &HashSet<usize>) -> u64 {
 	let mut res = 0;
 	for x in set.iter() {
@@ -204,13 +28,13 @@ fn decode_set(x: u64) ->HashSet<usize> {
 	return res;
 }
 
-struct Regexp {
+pub struct Regexp {
 	rules: HashMap<(usize, char), HashSet<usize>>,
 	end_states: HashSet<usize>
 }
 
 impl Regexp {
-	fn new(pattern: &String) -> Regexp {
+	pub 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();
@@ -260,7 +84,7 @@ impl Regexp {
 		return multistate.iter().any(|x| self.end_states.contains(x));
 	}
 
-	fn determinize(&self) -> RegexpDFA {
+	pub fn determinize(&self) -> RegexpDFA {
 		let mut rules: HashMap<(u64, char), u64> = HashMap::new();
 		let mut end_states: HashSet<u64> = HashSet::new();
 		if self.end_states.contains(&START) {end_states.insert(START as u64);}
@@ -299,13 +123,13 @@ impl Regexp {
 	}
 }
 
-struct RegexpDFA {
+pub struct RegexpDFA {
 	rules: HashMap<(u64, char), u64>,
 	end_states: HashSet<u64>
 }
 
 impl RegexpDFA {
-	fn eval(&self, s: String) -> bool {
+	pub fn eval(&self, s: String) -> bool {
 		let mut state = START as u64;
 
 		for c in s.chars() {
@@ -319,15 +143,3 @@ impl RegexpDFA {
 		return self.end_states.contains(&state);
 	}
 }
-
-fn main() {
-	let tests = ["", "a", "ab", "aabb", "abab", "abcd", "abcbcdbcd"];
-	for pattern in ["a*b*", "a+b+", "(ab)*", "(ab)+", "a((bc)*d)*"] {
-		println!("# {pattern}");
-		let r = Regexp::new(&pattern.to_string()).determinize();
-		for &t in tests.iter() {
-			println!("{t} {}", r.eval(t.to_string()));
-		}
-		println!();
-	}
-}