feat: allow underscores in integers

src/evaluator.rs

@@ -87,6 +87,7 @@ mod test {
     #[rstest]
     // Raw values
     #[case("1", "1")]
+    #[case("1_000", "1000")]
     #[case("\"uwu\"", "uwu")]
     #[case(":owo", ":owo")]
     #[case("()", "()")]

src/parser/lexer.rs

@@ -173,6 +173,11 @@ fn read_int(input: &mut Peekable<Chars>, first: char) -> Token {
     let mut raw_int = vec![first];
 
     while let Some(c) = input.peek() {
+        if *c == '_' {
+            input.next();
+            continue;
+        }
+
         if !c.is_ascii_digit() {
             break;
         }