implement multiline nested comments

src/bong/lexer.rs

@@ -116,12 +116,15 @@ fn make_number<T: Iterator<Item = char>>(
                 *col += 1;
                 if result.contains(&'.') {
                     iter.next();
-                    return Err(TokenError {
+                    let error = TokenError {
                         error: "unexpected token".to_string(),
                         col: *col,
                         line: *line,
-                    });
+                    };
+                    *col += 1;
+                    return Err(error);
                 }
+                *col += 1;
 
                 iter.next().expect(NO_MUT_PEEK_NEXT_MESSAGE);
                 result.push('.');
@@ -209,13 +212,67 @@ fn make_comment<T: Iterator<Item = char>>(
     *col += 2;
     match second_character {
         '/' => loop {
+            *col += 1;
             match iter.peek() {
                 Some('\n') | None => break Ok(Token::SlComment(String::from_iter(result))),
                 _ => result.push(iter.next().expect(NO_MUT_PEEK_NEXT_MESSAGE)),
             }
         },
         '*' => {
-            todo!();
+            let mut current = if let Some(c) = iter.next() {
+                c
+            } else {
+                return Err(TokenError {
+                    error: "unexpected EOF".to_string(),
+                    col: *col,
+                    line: *line,
+                });
+            };
+            let mut nesting = 0;
+            loop {
+                if let Some(next) = iter.peek() {
+                    println!("{current:?}|{next:?}|{result:?}");
+                    if current == '/' {
+                        if *next == '*' {
+                            result.push(current);
+                            current = iter.next().expect(NO_MUT_PEEK_NEXT_MESSAGE);
+                            result.push(current);
+                            current = iter.next().expect(NO_MUT_PEEK_NEXT_MESSAGE);
+                            nesting += 1;
+                        }
+                    } else if current == '*' {
+                        if *next == '/' {
+                            result.push(current);
+                            current = iter.next().expect(NO_MUT_PEEK_NEXT_MESSAGE);
+                            result.push(current);
+
+                            if nesting == 0 {
+                                break Ok(Token::MlComment(String::from_iter(result)));
+                            }
+
+                            if iter.peek().is_none() {
+                                return Err(TokenError {
+                                    error: "unexpected EOF".to_string(),
+                                    col: *col,
+                                    line: *line,
+                                });
+                            }
+                            current = iter.next().expect(NO_MUT_PEEK_NEXT_MESSAGE);
+
+                            nesting -= 1;
+                        }
+                    } else {
+                        result.push(current);
+                        current = iter.next().expect(NO_MUT_PEEK_NEXT_MESSAGE);
+                    }
+                } else {
+                    break Err(TokenError {
+                        error: "unexpected EOF".to_string(),
+                        col: *col,
+                        line: *line,
+                    });
+                }
+            }
         }
         c => Err(TokenError {
             error: format!("unexpected token {c}"),
@@ -356,4 +413,21 @@ mod tests {
             ]
         )
     }
+
+    #[test]
+    fn unnested_multiline_comment() {
+        let text = "/* hello */";
+        let tokens = lexer(text);
+        assert_eq!(tokens, vec![Token::MlComment("/* hello */".to_string()),])
+    }
+
+    #[test]
+    fn nested_multiline_comment() {
+        let text = "/* /* hello */ */";
+        let tokens = lexer(text);
+        assert_eq!(
+            tokens,
+            vec![Token::MlComment("/* /* hello */ */".to_string()),]
+        )
+    }
 }