diff --git a/.clang-format b/.clang-format
index 3afd345..c171fd6 100644
--- a/.clang-format
+++ b/.clang-format
@@ -14,6 +14,7 @@ AlignTrailingComments:                           true
 AllowAllArgumentsOnNextLine:                     false
 AllowAllConstructorInitializersOnNextLine:       true
 AllowAllParametersOfDeclarationOnNextLine:       false
+AllowShortCaseLabelsOnASingleLine:               true
 AllowShortLambdasOnASingleLine:                  All
 
 AlwaysBreakTemplateDeclarations:                 Yes
diff --git a/src/ast.cpp b/src/ast.cpp
index a756420..c8f05d3 100644
--- a/src/ast.cpp
+++ b/src/ast.cpp
@@ -56,8 +56,8 @@ Symbol::Symbol(const std::string& symbol)
 
 // -----------------------------------------
 
-Value::Value(const std::string& value)
-	: m_value(value)
+Value::Value(State state)
+	: m_state(state)
 {
 }
 
diff --git a/src/ast.h b/src/ast.h
index 363f643..75f32f8 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -6,7 +6,7 @@
 
 #pragma once
 
-#include <cstdint>    // int64_t
+#include <cstdint>    // int64_t, uint8_t
 #include <functional> // std::function
 #include <memory>     // std::shared_ptr
 #include <span>
@@ -180,15 +180,21 @@ private:
 // true, false, nil
 class Value final : public ASTNode {
 public:
-	explicit Value(const std::string& value);
+	enum State : uint8_t {
+		Nil,
+		True,
+		False,
+	};
+
+	explicit Value(State state);
 	virtual ~Value() = default;
 
 	virtual bool isValue() const override { return true; }
 
-	const std::string& value() const { return m_value; }
+	State state() const { return m_state; }
 
 private:
-	std::string m_value;
+	State m_state;
 };
 
 // -----------------------------------------
diff --git a/src/lexer.h b/src/lexer.h
index c8fbcb2..052fef8 100644
--- a/src/lexer.h
+++ b/src/lexer.h
@@ -33,7 +33,7 @@ struct Token {
 		At,           // @
 		String,       // "foobar"
 		Keyword,      // :keyword
-		Value,        // number, "true", "false", "nil", symbol
+		Value,        // number, "nil", "true", "false", symbol
 		Comment,      // ;
 		Error,
 	};
diff --git a/src/printer.cpp b/src/printer.cpp
index e2cbef8..e7399bb 100644
--- a/src/printer.cpp
+++ b/src/printer.cpp
@@ -124,6 +124,16 @@ void Printer::printImpl(ASTNodePtr node)
 		printSpacing();
 		m_print += format("{}", std::static_pointer_cast<Number>(node)->number());
 	}
+	else if (is<Value>(node_raw_ptr)) {
+		printSpacing();
+		std::string value;
+		switch (std::static_pointer_cast<Value>(node)->state()) {
+		case Value::Nil: value = "nil"; break;
+		case Value::True: value = "true"; break;
+		case Value::False: value = "false"; break;
+		}
+		m_print += format("{}", value);
+	}
 	else if (is<Symbol>(node_raw_ptr)) {
 		printSpacing();
 		m_print += format("{}", std::static_pointer_cast<Symbol>(node)->symbol());
diff --git a/src/reader.cpp b/src/reader.cpp
index 1b968e7..1e2a77d 100644
--- a/src/reader.cpp
+++ b/src/reader.cpp
@@ -318,6 +318,16 @@ ASTNodePtr Reader::readValue()
 		return makePtr<Number>(result);
 	}
 
+	if (token.symbol == "nil") {
+		return makePtr<Value>(Value::Nil);
+	}
+	else if (token.symbol == "true") {
+		return makePtr<Value>(Value::True);
+	}
+	else if (token.symbol == "false") {
+		return makePtr<Value>(Value::False);
+	}
+
 	return makePtr<Symbol>(token.symbol);
 }
 
@@ -373,7 +383,7 @@ void Reader::dumpImpl(ASTNodePtr node)
 
 	ASTNode* node_raw_ptr = node.get();
 	if (is<List>(node_raw_ptr)) {
-		List* list = static_cast<List*>(node_raw_ptr);
+		auto list = std::static_pointer_cast<List>(node);
 		print("{}", indentation);
 		print(fg(ruc::format::TerminalColor::Blue), "ListContainer");
 		print(" <");
@@ -389,22 +399,27 @@ void Reader::dumpImpl(ASTNodePtr node)
 	else if (is<String>(node_raw_ptr)) {
 		print("{}", indentation);
 		print(fg(ruc::format::TerminalColor::Yellow), "StringNode");
-		print(" <{}>", static_cast<String*>(node_raw_ptr)->data());
+		print(" <{}>", node);
 	}
 	else if (is<Keyword>(node_raw_ptr)) {
 		print("{}", indentation);
 		print(fg(ruc::format::TerminalColor::Yellow), "KeywordNode");
-		print(" <{}>", static_cast<Keyword*>(node_raw_ptr)->keyword());
+		print(" <{}>", node);
 	}
 	else if (is<Number>(node_raw_ptr)) {
 		print("{}", indentation);
 		print(fg(ruc::format::TerminalColor::Yellow), "NumberNode");
-		print(" <{}>", static_cast<Number*>(node_raw_ptr)->number());
+		print(" <{}>", node);
+	}
+	else if (is<Value>(node_raw_ptr)) {
+		print("{}", indentation);
+		print(fg(ruc::format::TerminalColor::Yellow), "ValueNode");
+		print(" <{}>", node);
 	}
 	else if (is<Symbol>(node_raw_ptr)) {
 		print("{}", indentation);
 		print(fg(ruc::format::TerminalColor::Yellow), "SymbolNode");
-		print(" <{}>", static_cast<Symbol*>(node_raw_ptr)->symbol());
+		print(" <{}>", node);
 	}
 	print("\n");
 }
diff --git a/src/reader.h b/src/reader.h
index 981fcd5..10bb2cf 100644
--- a/src/reader.h
+++ b/src/reader.h
@@ -47,7 +47,7 @@ private:
 	ASTNodePtr readDeref();         // @
 	ASTNodePtr readString();        // "foobar"
 	ASTNodePtr readKeyword();       // :keyword
-	ASTNodePtr readValue();         // number, "true", "false", "nil", symbol
+	ASTNodePtr readValue();         // number, "nil", "true", "false", symbol
 
 	void dumpImpl(ASTNodePtr node);