diff --git a/TODO.md b/TODO.md
index bf5622d1..cb82dc28 100644
--- a/TODO.md
+++ b/TODO.md
@@ -135,4 +135,4 @@
   * [ ] Write educational materials to learn Erg while creating applications (e.g. CLI chess game -> GUI chess game, calculator -> toy language)
 * [ ] Develop Dyne (CPython compatible VM)
 * [ ] Develop Kayser (WebAssembly backend)
-* [ ] Develop Barye (LLVM backend)
+* [ ] Develop Gal (LLVM backend)
diff --git a/compiler/erg_compiler/context/initialize/mod.rs b/compiler/erg_compiler/context/initialize/mod.rs
index bcf525df..35d607d0 100644
--- a/compiler/erg_compiler/context/initialize/mod.rs
+++ b/compiler/erg_compiler/context/initialize/mod.rs
@@ -1330,13 +1330,13 @@ impl Context {
         proc.register_superclass(Obj, &obj);
         // TODO: lambda
         proc.register_marker_trait(mono("Named"));
-        let mut func = Self::mono_class("Function", Self::TOP_LEVEL);
-        func.register_superclass(mono("Procedure"), &proc);
+        let mut func = Self::mono_class("Func", Self::TOP_LEVEL);
+        func.register_superclass(mono("Proc"), &proc);
         func.register_superclass(Obj, &obj);
         // TODO: lambda
         func.register_marker_trait(mono("Named"));
-        let mut qfunc = Self::mono_class("QuantifiedFunction", Self::TOP_LEVEL);
-        qfunc.register_superclass(mono("Function"), &func);
+        let mut qfunc = Self::mono_class("QuantifiedFunc", Self::TOP_LEVEL);
+        qfunc.register_superclass(mono("Func"), &func);
         qfunc.register_superclass(Obj, &obj);
         self.register_builtin_type(Obj, obj, Const);
         // self.register_type(mono("Record"), vec![], record, Const);
@@ -1423,9 +1423,9 @@ impl Context {
         self.register_builtin_type(array_mut_t, array_mut_, Const);
         self.register_builtin_type(range_t, range, Const);
         self.register_builtin_type(mono("Tuple"), tuple_, Const);
-        self.register_builtin_type(mono("Procedure"), proc, Const);
-        self.register_builtin_type(mono("Function"), func, Const);
-        self.register_builtin_type(mono("QuantifiedFunction"), qfunc, Const);
+        self.register_builtin_type(mono("Proc"), proc, Const);
+        self.register_builtin_type(mono("Func"), func, Const);
+        self.register_builtin_type(mono("QuantifiedFunc"), qfunc, Const);
     }
 
     fn init_builtin_funcs(&mut self) {
diff --git a/compiler/erg_compiler/context/inquire.rs b/compiler/erg_compiler/context/inquire.rs
index fb0b63e8..e78a42e0 100644
--- a/compiler/erg_compiler/context/inquire.rs
+++ b/compiler/erg_compiler/context/inquire.rs
@@ -1089,13 +1089,13 @@ impl Context {
                 }
             }
             Type::Quantified(_) => {
-                if let Some(res) = self.get_nominal_type_ctx(&mono("QuantifiedFunction")) {
+                if let Some(res) = self.get_nominal_type_ctx(&mono("QuantifiedFunc")) {
                     return Some(res);
                 }
             }
             Type::Subr(_subr) => match _subr.kind {
                 SubrKind::Func => {
-                    if let Some(res) = self.get_nominal_type_ctx(&mono("Function")) {
+                    if let Some(res) = self.get_nominal_type_ctx(&mono("Func")) {
                         return Some(res);
                     }
                 }
@@ -1157,7 +1157,7 @@ impl Context {
                 }
             }
             Type::Quantified(_) => {
-                if let Some(res) = self.get_mut_nominal_type_ctx(&mono("QuantifiedFunction")) {
+                if let Some(res) = self.get_mut_nominal_type_ctx(&mono("QuantifiedFunc")) {
                     return Some(res);
                 }
             }
diff --git a/compiler/erg_parser/lex.rs b/compiler/erg_parser/lex.rs
index f7196e1c..cd1631d5 100644
--- a/compiler/erg_parser/lex.rs
+++ b/compiler/erg_parser/lex.rs
@@ -285,6 +285,62 @@ impl Lexer /*<'a>*/ {
         Ok(())
     }
 
+    fn lex_multi_line_comment(&mut self) -> LexResult<()> {
+        let mut s = "".to_string();
+        let mut nest_level = 0;
+        loop {
+            match self.peek_cur_ch() {
+                Some(c) => {
+                    if let Some(next_c) = self.peek_next_ch() {
+                        match (c, next_c) {
+                            ('#', '[') => nest_level += 1,
+                            (']', '#') => {
+                                nest_level -= 1;
+                                if nest_level == 0 {
+                                    return Ok(());
+                                }
+                            }
+                            _ => {}
+                        }
+                        if c == '\n' {
+                            self.lineno_token_starts += 1;
+                            self.col_token_starts = 0;
+                        }
+                        s.push(self.consume().unwrap());
+                    }
+                    if Self::is_bidi(self.peek_cur_ch().unwrap()) {
+                        let comment = self.emit_token(Illegal, &s);
+                        return Err(LexError::syntax_error(
+                            0,
+                            comment.loc(),
+                            switch_lang!(
+                                "japanese" => "不正なユニコード文字(双方向オーバーライド)がコメント中に使用されています",
+                                "simplified_chinese" => "注释中使用了非法的unicode字符（双向覆盖）",
+                                "traditional_chinese" => "註釋中使用了非法的unicode字符（雙向覆蓋）",
+                                "english" => "invalid unicode character (bi-directional override) in comments",
+                            ),
+                            None,
+                        ));
+                    }
+                }
+                None => {
+                    let comment = self.emit_token(Illegal, &s);
+                    return Err(LexError::syntax_error(
+                        0,
+                        comment.loc(),
+                        switch_lang!(
+                        "japanese" => "複数行コメントが]#で閉じられていません",
+                        "simplified_chinese" => "未用]#号结束的多处评论",
+                        "traditional_chinese" => "多條評論未用]#關閉",
+                        "english" => "Multi-comment is not closed with ]#",
+                        ),
+                        None,
+                    ));
+                }
+            }
+        }
+    }
+
     fn lex_space_indent_dedent(&mut self) -> Option<LexResult<Token>> {
         let is_toplevel = self.cursor > 0
             && !self.indent_stack.is_empty()
@@ -349,6 +405,11 @@ impl Lexer /*<'a>*/ {
         }
         // ignore indents if the current line is a comment
         if let Some('#') = self.peek_cur_ch() {
+            if let Some('[') = self.peek_next_ch() {
+                if let Err(e) = self.lex_multi_line_comment() {
+                    return Some(Err(e));
+                }
+            }
             if let Err(e) = self.lex_comment() {
                 return Some(Err(e));
             }
@@ -562,6 +623,7 @@ impl Lexer /*<'a>*/ {
                         'r' => s.push('\r'),
                         'n' => s.push('\n'),
                         '\'' => s.push('\''),
+                        '"' => s.push('"'),
                         't' => s.push_str("    "), // tab is invalid, so changed into 4 whitespace
                         '\\' => s.push('\\'),
                         _ => {
@@ -630,6 +692,11 @@ impl Iterator for Lexer /*<'a>*/ {
             return indent_dedent;
         }
         if let Some('#') = self.peek_cur_ch() {
+            if let Some('[') = self.peek_next_ch() {
+                if let Err(e) = self.lex_multi_line_comment() {
+                    return Some(Err(e));
+                }
+            }
             if let Err(e) = self.lex_comment() {
                 return Some(Err(e));
             }
diff --git a/compiler/erg_parser/tests/comment.er b/compiler/erg_parser/tests/comment.er
new file mode 100644
index 00000000..d795f412
--- /dev/null
+++ b/compiler/erg_parser/tests/comment.er
@@ -0,0 +1,7 @@
+#[
+    aa
+ #[ aa ]#
+aa
+]#
+
+a = 1
diff --git a/compiler/erg_parser/tests/test1_basic_syntax.er b/compiler/erg_parser/tests/test1_basic_syntax.er
index ffd77c3f..4eddb3ff 100644
--- a/compiler/erg_parser/tests/test1_basic_syntax.er
+++ b/compiler/erg_parser/tests/test1_basic_syntax.er
@@ -1,12 +1,24 @@
-# 基本的な構文をパーサーがパスできるかチェックする
-# Check that a parser can pass the basic syntax
+#[
+基本的な構文をパーサーがパスできるかチェックする
+Check that a parser can pass the basic syntax
+    #[
+        `#[`から`]#`までが複数行コメントとして扱われる
+        コメント内部で入れ子で複数行コメントを付けれるが、閉じ忘れに注意
+        The comment from `#[` to `]#` is treated as a multi-line comment.
+        Nested multi-line comments can be added inside comments, but be careful not to forget to close them.
+    ]#
+]#
 
 _a = 1_234 + 1113.* 3_000.2e-4 ** 0003 * .4
 a, _, ...b = five_elem_tuple
 f x, y =
     x + y
 if! True, do!:
-    print! "\\hello, world\""
+    print! "\"\\hello, world\\\""
+    #[
+        indented comment
+dedented comment
+    ]#
     10.times! do!:
         if! x.y.z, do!:
             print! ""
diff --git a/compiler/erg_parser/tests/test3_literal_syntax.er b/compiler/erg_parser/tests/test3_literal_syntax.er
index 2bbae620..d9eb12d5 100644
--- a/compiler/erg_parser/tests/test3_literal_syntax.er
+++ b/compiler/erg_parser/tests/test3_literal_syntax.er
@@ -9,7 +9,7 @@
 0.00, -0.0, .1, 400.
 
 # Str Literal
-"", "a", "こんにちは", "\" \\ "
+"", "a", "こんにちは", "\"\\", "\"\'\\\0\r\n\t"
 
 # Boolean Litteral
 True, False
diff --git a/compiler/erg_parser/tests/tokenize_test.rs b/compiler/erg_parser/tests/tokenize_test.rs
index 47744926..fca29d8b 100644
--- a/compiler/erg_parser/tests/tokenize_test.rs
+++ b/compiler/erg_parser/tests/tokenize_test.rs
@@ -18,7 +18,6 @@ fn test_lexer_for_basic() -> ParseResult<()> {
     let mut lexer = Lexer::new(Input::File(FILE1.into()));
     let newline = "\n";
     let /*mut*/ token_array = vec![
-        (Newline, newline),
         (Newline, newline),
         (Newline, newline),
         (Symbol, "_a"),
@@ -37,7 +36,7 @@ fn test_lexer_for_basic() -> ParseResult<()> {
         (Comma, ","),
         (UBar, "_"),
         (Comma, ","),
-        (Spread, "..."), // EllipsisLit
+        (EllipsisLit, "..."),
         (Symbol, "b"),
         (Equal, "="),
         (Symbol, "five_elem_tuple"),
@@ -62,7 +61,8 @@ fn test_lexer_for_basic() -> ParseResult<()> {
         (Newline, newline),
         (Indent, "    "),
         (Symbol, "print!"),
-        (StrLit, "\"\\\\hello, world\\\"\""),
+        (StrLit, "\"\"\\hello, world\\\"\""),
+        (Newline, newline),
         (Newline, newline),
         (NatLit, "10"),
         (Dot, "."),
@@ -264,7 +264,9 @@ fn test_lexer_for_literals() -> ParseResult<()> {
         (Comma, ","),
         (StrLit, "\"こんにちは\""),
         (Comma, ","),
-        (StrLit, "\"\\\" \\\\ \""),
+        (StrLit, "\"\"\\\""),
+        (Comma, ","),
+        (StrLit, "\"\"\'\\\0\r\n    \""),
         (Newline, newline),
         (Newline, newline),
         (Newline, newline),