Support var

README.md

@@ -7,7 +7,7 @@
 - **0-based 索引**：数组和列表从 0 开始索引
 - **明确的类型系统**：区分 list 和 map
 - **类支持**：支持 class 定义，包含字段和方法
-- **静态类型声明**：变量需要类型声明（number, string, bool, list, map）
+- **类型推断**：使用 `var` 关键字自动推断变量类型，也支持显式类型注解
 - **类 Lua 的 API**：提供简单的嵌入式 API
 
 ## 语法示例
@@ -15,15 +15,21 @@
 ### 基本类型
 
 ```javascript
-number x = 10;
-string name = "Alice";
-bool flag = true;
+// 类型自动推断
+var x = 10;
+var name = "Alice";
+var flag = true;
+
+// 显式类型声明
+var y : number = 3.14;
+var title : string = "Developer";
+var active : bool = false;
 ```
 
 ### List（0-indexed）
 
 ```javascript
-list numbers = [10, 20, 30];
+var numbers = [10, 20, 30];  // 自动推断为 list
 print(numbers[0]);  // 输出: 10
 numbers[1] = 99;
 ```
@@ -31,7 +37,7 @@ numbers[1] = 99;
 ### Map
 
 ```javascript
-map person = {"name": "Bob", "age": "25"};
+var person = {"name": "Bob", "age": "25"};  // 自动推断为 map
 print(person["name"]);  // 输出: Bob
 person["city"] = "New York";
 ```
@@ -43,15 +49,15 @@ func add(number a, number b) -> number {
     return a + b;
 }
 
-number result = add(10, 20);
+var result = add(10, 20);  // 自动推断返回值类型
 ```
 
 ### 类
 
 ```javascript
 class Person {
-    number age;
-    string name;
+    var age : number;    // 类成员必须显式声明类型
+    var name : string;
     
     func sayHi() -> string {
         print(name, "says: I'm", age, "years old");
@@ -59,7 +65,7 @@ class Person {
     }
 }
 
-Person p;
+var p : Person;  // 实例化类
 p.age = 10;
 p.name = "Peter";
 p.sayHi();
@@ -76,14 +82,14 @@ if (x > 10) {
 }
 
 // while loop
-number i = 0;
+var i = 0;
 while (i < 5) {
     print("Count:", i);
     i = i + 1;
 }
 
 // for loop
-for (number j = 0; j < 3; j = j + 1) {
+for (var j = 0; j < 3; j = j + 1) {
     print("For loop:", j);
 }
 ```
@@ -117,8 +123,8 @@ int main() {
     // 执行脚本字符串
     const char* script = R"(
         class Person {
-            number age;
-            string name;
+            var age : number;
+            var name : string;
             
             func sayHi() -> string {
                 print(name, "says: I'm", age, "years old");
@@ -126,7 +132,7 @@ int main() {
             }
         }
         
-        Person p;
+        var p : Person;
         p.age = 10;
         p.name = "Peter";
         p.sayHi();
@@ -203,10 +209,10 @@ camellya/
 |------|-----|----------|
 | 索引起始 | 1 | 0 |
 | Table | 统一的 table | 区分 list 和 map |
-| 类型 | 动态 | 静态声明 |
+| 类型 | 动态 | 类型推断 + 可选类型注解 |
 | 类 | 通过 metatable | 原生支持 |
 | 语法 | `function` | `func` |
-| 类型注解 | 无 | 必须声明 |
+| 变量声明 | 无需声明 | `var` 关键字 |
 
 ## 许可证
 

example.chun

@@ -2,8 +2,8 @@
 // This demonstrates the Person class from the specification
 
 class Person {
-    number age;
-    string name;
+    var age : number;
+    var name : string;
     
     func sayHi() -> string {
         print(name, "says: I'm", age, "years old");
@@ -18,7 +18,7 @@ class Person {
 }
 
 // Create an instance
-Person p;
+var p : Person;
 p.age = 10;
 p.name = "Peter";
 
@@ -29,12 +29,12 @@ p.sayHi();
 
 // Test lists (0-indexed)
 print("\n=== List Demo ===");
-list numbers = [1, 2, 3, 4, 5];
+var numbers = [1, 2, 3, 4, 5];
 print("List:", numbers);
 print("First element (index 0):", numbers[0]);
 print("测试 element (index 2):", numbers[2]);
 
-for(number i = 0; i < len(numbers); i = i + 1) {
+for(var i = 0; i < len(numbers); i = i + 1) {
     print("List element", numbers[i]);
 }
 
@@ -44,7 +44,7 @@ while(true) {
 }
 // Test maps
 print("\n=== Map Demo ===");
-map config = {"host": "localhost", "port": "8080"};
+var config = {"host": "localhost", "port": "8080"};
 print("Config:", config);
 print("Host:", config["host"]);
 

src/ast.h

@@ -133,12 +133,13 @@ struct ExprStmt : public Stmt {
 };
 
 struct VarDecl : public Stmt {
-    std::string type_name;
+    std::string type_name;  // Can be empty if type inference is needed
     std::string name;
     ExprPtr initializer;
+    bool infer_type;  // true if type should be inferred from initializer
     
-    VarDecl(std::string type_name, std::string name, ExprPtr initializer = nullptr)
-        : type_name(std::move(type_name)), name(std::move(name)), initializer(std::move(initializer)) {}
+    VarDecl(std::string type_name, std::string name, ExprPtr initializer = nullptr, bool infer_type = false)
+        : type_name(std::move(type_name)), name(std::move(name)), initializer(std::move(initializer)), infer_type(infer_type) {}
 };
 
 struct BlockStmt : public Stmt {

src/interpreter.cpp

@@ -367,7 +367,23 @@ void Interpreter::exec_var_decl(const VarDecl& stmt) {
     
     if (stmt.initializer) {
         value = evaluate(*stmt.initializer);
+        
+        // If type inference is needed, we use the value directly
+        if (stmt.infer_type) {
+            // Type is automatically inferred from the initializer value
+            environment->define(stmt.name, value);
+            return;
+        }
+        
+        // If explicit type is provided, verify the value matches
+        // (This is a simple check, could be more sophisticated)
+        if (!stmt.type_name.empty()) {
+            // Just use the value; type checking could be added here
+            environment->define(stmt.name, value);
+            return;
+        }
     } else {
+        // No initializer, use default value based on type
         value = create_default_value(stmt.type_name);
     }
     

src/parser.cpp

@@ -94,14 +94,9 @@ StmtPtr Parser::declaration() {
     if (match({TokenType::FUNC})) {
         return function_declaration();
     }
-    if (check(TokenType::NUMBER) || check(TokenType::STRING) || 
-        check(TokenType::BOOL) || check(TokenType::LIST) || 
-        check(TokenType::MAP) || check(TokenType::IDENTIFIER)) {
-        // Type name followed by identifier
-        Token lookahead = tokens_[current_];
-        if (current_ + 1 < tokens_.size() && tokens_[current_ + 1].type == TokenType::IDENTIFIER) {
-            return var_declaration();
-        }
+    // Handle var keyword for variable declaration
+    if (match({TokenType::VAR})) {
+        return var_declaration();
     }
     
     return statement();
@@ -118,8 +113,10 @@ StmtPtr Parser::class_declaration() {
         if (check(TokenType::FUNC)) {
             advance();
             members.push_back(function_declaration());
-        } else {
+        } else if (match({TokenType::VAR})) {
             members.push_back(var_declaration());
+        } else {
+            throw error(peek(), "Expected 'var' or 'func' in class body.");
         }
     }
     
@@ -161,17 +158,35 @@ StmtPtr Parser::function_declaration() {
 }
 
 StmtPtr Parser::var_declaration() {
-    Token type_token = advance();
-    std::string type_name = type_token.lexeme;
-    Token name = consume(TokenType::IDENTIFIER, "Expected variable name.");
+    // var keyword has already been consumed
+    Token name = consume(TokenType::IDENTIFIER, "Expected variable name after 'var'.");
     
+    std::string type_name;
+    bool infer_type = false;
     ExprPtr initializer = nullptr;
-    if (match({TokenType::EQUAL})) {
+    
+    // Check for explicit type annotation: var x : type
+    if (match({TokenType::COLON})) {
+        Token type_token = advance();
+        type_name = type_token.lexeme;
+        
+        // Optional initializer
+        if (match({TokenType::EQUAL})) {
+            initializer = expression();
+        }
+    } else {
+        // No type annotation, must have initializer for type inference
+        if (!match({TokenType::EQUAL})) {
+            throw error(peek(), "Variable declaration without type annotation must have an initializer.");
+        }
         initializer = expression();
+        infer_type = true;
+        type_name = ""; // Will be inferred at runtime
     }
+    
     consume(TokenType::SEMICOLON, "Expected ';' after variable declaration.");
     
-    return std::make_unique<VarDecl>(type_name, name.lexeme, std::move(initializer));
+    return std::make_unique<VarDecl>(type_name, name.lexeme, std::move(initializer), infer_type);
 }
 
 StmtPtr Parser::statement() {

tests/test_basic.cpp

@@ -9,9 +9,9 @@ using namespace camellya;
 TEST_CASE("basic arithmetic", "[script]") {
     State state;
     const char* script = R"(
-        number x = 10;
-        number y = 20;
-        number z = x + y;
+        var x = 10;
+        var y = 20;
+        var z = x + y;
     )";
 
     REQUIRE(state.do_string(script));
@@ -31,7 +31,7 @@ TEST_CASE("basic function", "[script][func]") {
         func add(number x, number y) -> number {
             return x + y;
         }
-        number z = add(10, 20);
+        var z = add(10, 20);
     )";
 
     REQUIRE(state.do_string(script));
@@ -48,7 +48,7 @@ TEST_CASE("basic function", "[script][func]") {
 TEST_CASE("list indexing is 0-based", "[list]") {
     State state;
     const char* script = R"(
-        list numbers = [10, 20, 30];
+        var numbers = [10, 20, 30];
     )";
 
     REQUIRE(state.do_string(script));
@@ -78,8 +78,8 @@ TEST_CASE("class init is called on declaration", "[class][init]") {
     State state;
     const char* script = R"(
         class Person {
-            number age;
-            string name;
+            var age : number;
+            var name : string;
 
             func init() -> nil {
                 age = 18;
@@ -91,8 +91,8 @@ TEST_CASE("class init is called on declaration", "[class][init]") {
             }
         }
 
-        Person p;
-        number a = p.getAge();
+        var p : Person;
+        var a = p.getAge();
     )";
 
     REQUIRE(state.do_string(script));
@@ -152,8 +152,8 @@ TEST_CASE("class init is called on declaration", "[class][init]") {
 TEST_CASE("loop break", "[script][loop]") {
     State state;
     const char* script = R"(
-        number sum = 0;
-        for (number i = 0; i < 10; i = i + 1) {
+        var sum = 0;
+        for (var i = 0; i < 10; i = i + 1) {
             if (i == 5) {
                 break;
             }
@@ -171,8 +171,8 @@ TEST_CASE("loop break", "[script][loop]") {
 TEST_CASE("loop continue", "[script][loop]") {
     State state;
     const char* script = R"(
-        number sum = 0;
-        for (number i = 0; i < 5; i = i + 1) {
+        var sum = 0;
+        for (var i = 0; i < 5; i = i + 1) {
             if (i == 2) {
                 continue;
             }
@@ -190,8 +190,8 @@ TEST_CASE("loop continue", "[script][loop]") {
 TEST_CASE("while break and continue", "[script][loop]") {
     State state;
     const char* script = R"(
-        number i = 0;
-        number sum = 0;
+        var i = 0;
+        var sum = 0;
         while (i < 10) {
             i = i + 1;
             if (i == 3) {