diff --git a/src/ast.cpp b/src/ast.cpp
index 803a627..eb4b37f 100644
--- a/src/ast.cpp
+++ b/src/ast.cpp
@@ -26,6 +26,13 @@ void Collection::addNode(ASTNode* node)
 
 // -----------------------------------------
 
+void HashMap::addElement(const std::string& key, ASTNode* value)
+{
+	m_elements.emplace(key, value);
+}
+
+// -----------------------------------------
+
 String::String(const std::string& data)
 	: m_data(data)
 {
diff --git a/src/ast.h b/src/ast.h
index 0fcd2d0..f00e1a0 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -12,6 +12,7 @@
 #include <string>
 #include <string_view>
 #include <typeinfo> // typeid
+#include <unordered_map>
 #include <vector>
 
 #include "ruc/format/formatter.h"
@@ -90,13 +91,21 @@ public:
 // -----------------------------------------
 
 // {}
-class HashMap final : public Collection {
+class HashMap final : public ASTNode {
 public:
 	HashMap() = default;
 	virtual ~HashMap() = default;
 
-	virtual bool isCollection() const override { return false; }
 	virtual bool isHashMap() const override { return true; }
+
+	void addElement(const std::string& key, ASTNode* value);
+
+	const std::unordered_map<std::string, ASTNode*>& elements() const { return m_elements; }
+	size_t size() const { return m_elements.size(); }
+	bool empty() const { return m_elements.size() == 0; }
+
+private:
+	std::unordered_map<std::string, ASTNode*> m_elements;
 };
 
 // -----------------------------------------
diff --git a/src/eval.cpp b/src/eval.cpp
index 85a43f0..23bd708 100644
--- a/src/eval.cpp
+++ b/src/eval.cpp
@@ -63,9 +63,12 @@ ASTNode* Eval::evalAst(ASTNode* ast, Environment* env)
 		return result;
 	}
 	else if (is<HashMap>(ast)) {
-		// TODO
-		VERIFY_NOT_REACHED();
-		return nullptr;
+		auto result = new HashMap();
+		auto elements = static_cast<HashMap*>(ast)->elements();
+		for (auto& element : elements) {
+			result->addElement(element.first, evalImpl(element.second, env));
+		}
+		return result;
 	}
 
 	return ast;
diff --git a/src/lexer.cpp b/src/lexer.cpp
index 71e970b..91053d4 100644
--- a/src/lexer.cpp
+++ b/src/lexer.cpp
@@ -216,7 +216,7 @@ bool Lexer::consumeKeyword()
 bool Lexer::consumeValue()
 {
 	size_t column = m_column;
-	std::string value = "";
+	std::string value;
 
 	static std::unordered_set<char> exit = {
 		'[',
@@ -259,7 +259,7 @@ bool Lexer::consumeValue()
 bool Lexer::consumeComment()
 {
 	size_t column = m_column;
-	std::string comment = "";
+	std::string comment;
 
 	ignore(); // ;
 
diff --git a/src/printer.cpp b/src/printer.cpp
index 8e17355..753d6c3 100644
--- a/src/printer.cpp
+++ b/src/printer.cpp
@@ -78,8 +78,9 @@ void Printer::dumpImpl(ASTNode* node)
 		m_firstNode = false;
 		m_previousNodeIsList = true;
 		HashMap* hash_map = static_cast<HashMap*>(node);
-		for (size_t i = 0; i < hash_map->nodes().size(); ++i) {
-			dumpImpl(hash_map->nodes()[i]);
+		for (auto element : hash_map->elements()) {
+			print("{} ", element.first.front() == 0x7f ? ":" + element.first.substr(1) : element.first); // 127
+			dumpImpl(element.second);
 			m_previousNodeIsList = false;
 		}
 		print("}}");
diff --git a/src/reader.cpp b/src/reader.cpp
index d896a5f..97751c8 100644
--- a/src/reader.cpp
+++ b/src/reader.cpp
@@ -193,9 +193,27 @@ ASTNode* Reader::readHashMap()
 {
 	ignore(); // {
 
-	HashMap* vector = new HashMap();
+	HashMap* hash_map = new HashMap();
 	while (!isEOF() && peek().type != Token::Type::BraceClose) {
-		vector->addNode(readImpl());
+		ASTNode* key = readImpl();
+		ASTNode* value = readImpl();
+
+		if (!key && !value) {
+			break;
+		}
+
+		if (!key || !value) {
+			Error::the().addError("hash-map requires an even-sized list");
+			return nullptr;
+		}
+
+		if (!is<String>(key) && !is<Keyword>(key)) {
+			Error::the().addError(format("{} is not a string or keyword", key));
+			return nullptr;
+		}
+
+		std::string keyString = is<String>(key) ? static_cast<String*>(key)->data() : static_cast<Keyword*>(key)->keyword();
+		hash_map->addElement(keyString, value);
 	}
 
 	if (!consumeSpecific(Token { .type = Token::Type::BraceClose })) { // }
@@ -203,7 +221,7 @@ ASTNode* Reader::readHashMap()
 		m_is_unbalanced = true;
 	}
 
-	return vector;
+	return hash_map;
 }
 
 ASTNode* Reader::readQuote()