v0.4.2-alpha

[Fix][Impl] 为了消除类构造带来的语法歧义，同时保持实现简洁和括号省略的语法，自此版本，引入了 `new` 操作符
            造成歧义的原方法：
                if a == A{}
            条件是 a == A，还是 a == A{} ?

            因此，现在使用 new a_struct{}来构造类
[Opti] 相较于 Fig v0.4.1-alpha版本，release O3同编译条件下
       Fib普通递归法性能提升 ~50%
       具体方式:
            增加了小整数优化，-128~127的整数现在会直接从IntPool获取而不是新构造
            ...忘了
[Fix] 类构造 shorthand模式忘写了，现在补上了
[Feat][Impl] 类型声明现在接受一个表达式，原为Identifier。实现 var start: time.Time = time.now() 的效果
             这是符合语法和语言特性的支持，类型为一等公民。类似Python的 <class 'type'>

[Impl] 修改了部分错误输出的细节

ExampleCodes/1-Variables.fig

@@ -11,3 +11,69 @@ invalid!
 
 const Pi := 3.14; // recommended, auto detect type
 // equal -> const Pi: Double = 3.14;
+
+/*
+In fig, we have 13 builtin-type
+
+01  Any
+02  Null
+03  Int
+04  String
+05  Bool
+06  Double
+07  Function
+08  StructType
+09  StructInstance
+10  List
+11  Map
+12  Module
+13  InterfaceType
+
+3, 4, 5, 6, 10, 11 are initable
+
+value system:
+    object is immutable
+    (included basic types: Int, String...)
+
+    `variable` is a name, refers to an object
+    assignment is to bind name to value
+    
+    Example: var a := 10;
+
+    [name] 'a' ---> variable slot (name, declared type, access modifier, [value) ---> ObjectPtr ---> raw Object class
+               bind                                                              bind (shared_ptr)
+
+    For example:
+        var a := 10;
+        var b := 10;
+
+        `a` and `b` reference to the same object in memory
+
+        a = 20;
+
+        now a refers to a new object (20, Int)
+
+        what about complex types?
+        they actually have same behaviors with basic types
+
+        var a := [1, 2, 3, 4];
+        var b := a;
+
+        > a
+          [1, 2, 3, 4]
+        > b
+          [1, 2, 3, 4]
+        
+        set a[0] to 5
+
+        > a
+          [5, 2, 3, 4]
+        > b
+          [5, 2, 3, 4]
+
+        Why did such a result occur?
+    
+        " `a` and `b` reference to the same object in memory "
+
+        If you wish to obtain a copy, use List {a} to deeply copy it
+*/

ExampleCodes/SpeedTest/fibBenchmark.fig

@@ -0,0 +1,65 @@
+import std.io;
+import std.time;
+
+func benchmark(fn: Function, arg: Any) -> Null
+{
+    io.println("Testing fn:", fn, "with arg:", arg);
+    const start := time.now();
+    
+    const result := fn(arg);
+    
+    const end := time.now();
+    const duration := new time.Time{
+        end.since(start)
+    };
+    io.println("=" * 50);
+    io.println("fn returns:", result, "\n");
+    io.println("Cost:", duration.toSeconds(), "s");
+    io.println("     ", duration.toMillis(), "ms");
+}
+
+var memo := {};
+
+func fib_memo(x)
+{
+    if memo.contains(x)
+    {
+        return memo.get(x);
+    }
+    if x <= 1
+    {
+        memo[x] = x;
+        return x;
+    }
+    var result := fib_memo(x - 1) + fib_memo(x - 2);
+    memo[x] = result;
+    return result;
+}
+
+func fib_iter(n)
+{
+    var a := 0;
+    var b := 1;
+    for var i := 0; i < n; i = i + 1
+    {
+        var temp := a + b;
+        a = b;
+        b = temp;
+    }
+    return a;
+}
+
+func fib(x)
+{
+    if x <= 1
+    {
+        return x;
+    }
+    return fib(x - 1) + fib(x - 2);
+}
+
+const n := 28;
+
+benchmark(fib, n);
+benchmark(fib_memo, n);
+benchmark(fib_iter, n);

fig-vscode/package.json

@@ -2,7 +2,7 @@
   "name": "fig-vscode",
   "displayName": "Fig Language",
   "description": "VSCode extension for Fig language with syntax highlighting",
-  "version": "0.0.2",
+  "version": "0.4.2",
   "publisher": "PuqiAR",
   "engines": {
     "vscode": "^1.90.0"

fig-vscode/syntaxes/fig.tmLanguage.json

@@ -57,7 +57,7 @@
       "patterns": [
         {
           "name": "keyword.control.fig",
-          "match": "\\b(and|or|not|import|func|var|const|final|while|for|if|else|struct|interface|impl|public|return|break|continue|try|catch|throw)\\b"
+          "match": "\\b(and|or|not|import|func|var|const|final|while|for|if|else|new|struct|interface|impl|public|return|break|continue|try|catch|throw)\\b"
         },
         { "name": "constant.language.fig", "match": "\\b(true|false|null)\\b" }
       ]

src/Ast/Statements/FunctionDefSt.hpp

@@ -23,14 +23,14 @@ namespace Fig::Ast
         FString name;
         FunctionParameters paras;
         bool isPublic;
-        FString retType;
+        Expression retType; 
         BlockStatement body;
-        FunctionDefSt() :
-            retType(ValueType::Null.name)
+
+        FunctionDefSt()
         {
             type = AstType::FunctionDefSt;
         }
-        FunctionDefSt(FString _name, FunctionParameters _paras, bool _isPublic, FString _retType, BlockStatement _body)
+        FunctionDefSt(FString _name, FunctionParameters _paras, bool _isPublic, Expression _retType, BlockStatement _body)
         {
             type = AstType::FunctionDefSt;
 

src/Ast/Statements/InterfaceDefSt.hpp

@@ -25,7 +25,7 @@ namespace Fig::Ast
     {
         FString name;
         FunctionParameters paras;
-        FString returnType;
+        Expression returnType;
 
         BlockStatement defaultBody = nullptr; // nullptr is non-default func
 

src/Ast/Statements/StructDefSt.hpp

@@ -12,12 +12,12 @@ namespace Fig::Ast
     {
         AccessModifier am;
         FString fieldName;
-        FString tiName;
+        Expression declaredType; 
         Expression defaultValueExpr;
 
         StructDefField() {}
-        StructDefField(AccessModifier _am, FString _fieldName, FString _tiName, Expression _defaultValueExpr) :
-            am(std::move(_am)), fieldName(std::move(_fieldName)), tiName(std::move(_tiName)), defaultValueExpr(std::move(_defaultValueExpr))
+        StructDefField(AccessModifier _am, FString _fieldName,  Expression _declaredType, Expression _defaultValueExpr) :
+            am(std::move(_am)), fieldName(std::move(_fieldName)), declaredType(std::move(_declaredType)), defaultValueExpr(std::move(_defaultValueExpr))
         {
         }
     };

src/Ast/Statements/VarDef.hpp

@@ -11,22 +11,28 @@ namespace Fig::Ast
         bool isPublic;
         bool isConst;
         FString name;
-        FString typeName;
+        // FString typeName;
+        Expression declaredType;
         Expression expr;
 
-        VarDefAst() :
-            typeName(ValueType::Any.name)
+        bool followupType;
+
+        VarDefAst()
         {
             type = AstType::VarDefSt;
+            declaredType = nullptr;
+            expr = nullptr;
+            followupType = false;
         }
-        VarDefAst(bool _isPublic, bool _isConst, FString _name, FString _info, Expression _expr) :
-            typeName(std::move(_info))
+        VarDefAst(bool _isPublic, bool _isConst, FString _name, Expression _declaredType, Expression _expr, bool _followupType)
         {
             type = AstType::VarDefSt;
             isPublic = _isPublic;
             isConst = _isConst;
             name = std::move(_name);
+            declaredType = std::move(_declaredType);
             expr = std::move(_expr);
+            followupType = _followupType;
         }
     };
 

src/Ast/astBase.hpp

@@ -26,14 +26,15 @@ namespace Fig::Ast
         TernaryExpr,
 
         /* Postfix */
-        MemberExpr, // a.b
-        IndexExpr,  // a[b]
+        MemberExpr,   // a.b
+        IndexExpr,    // a[b]
         FunctionCall, // a()
 
         /* Literals */
         ListExpr,  // [1, "2", 3
         TupleExpr, // (1, 2, 3)
         MapExpr,   // {a: 1}
+
         InitExpr,  // struct{"123", 456}
         FunctionLiteralExpr,
 
@@ -119,30 +120,20 @@ namespace Fig::Ast
 
         _AstBase() {}
 
-        void setAAI(AstAddressInfo _aai)
-        {
-            aai = std::move(_aai);
-        }
+        void setAAI(AstAddressInfo _aai) { aai = std::move(_aai); }
 
         virtual FString typeName()
         {
-            return FString::fromStringView(
-                FStringView::fromBasicStringView(magic_enum::enum_name(type)));
+            return FString::fromStringView(FStringView::fromBasicStringView(magic_enum::enum_name(type)));
         }
         virtual FString toString()
         {
             return FString(std::format("<Base Ast '{}' at {}:{}>", typeName().toBasicString(), aai.line, aai.column));
         }
 
-        AstAddressInfo getAAI()
-        {
-            return aai;
-        }
+        AstAddressInfo getAAI() { return aai; }
 
-        AstType getType()
-        {
-            return type;
-        }
+        AstType getType() { return type; }
     };
 
     class StatementAst : public _AstBase
@@ -150,10 +141,7 @@ namespace Fig::Ast
     public:
         using _AstBase::_AstBase;
         using _AstBase::operator=;
-        StatementAst()
-        {
-            type = AstType::StatementBase;
-        }
+        StatementAst() { type = AstType::StatementBase; }
 
         virtual FString toString() override
         {
@@ -164,10 +152,7 @@ namespace Fig::Ast
     class EofStmt final : public StatementAst
     {
     public:
-        EofStmt()
-        {
-            type = AstType::StatementBase;
-        }
+        EofStmt() { type = AstType::StatementBase; }
 
         virtual FString toString() override
         {
@@ -180,10 +165,7 @@ namespace Fig::Ast
     public:
         using _AstBase::_AstBase;
         using _AstBase::operator=;
-        ExpressionAst()
-        {
-            type = AstType::ExpressionBase;
-        }
+        ExpressionAst() { type = AstType::ExpressionBase; }
 
         virtual FString toString() override
         {
@@ -242,41 +224,22 @@ namespace Fig::Ast
     static const std::unordered_set<Operator> unaryOps{
         Operator::Not,      // !
         Operator::Subtract, // -
-        Operator::BitNot, // ~
+        Operator::BitNot,   // ~
 
         Operator::BitAnd, // reference operator &
     };
     static const std::unordered_set<Operator> binaryOps{
-        Operator::Add,
-        Operator::Subtract,
-        Operator::Multiply,
-        Operator::Divide,
-        Operator::Modulo,
-        Operator::Power,
-        Operator::And,
-        Operator::Or,
+        Operator::Add,         Operator::Subtract,     Operator::Multiply,    Operator::Divide,
+        Operator::Modulo,      Operator::Power,        Operator::And,         Operator::Or,
 
-        Operator::Equal,
-        Operator::NotEqual,
-        Operator::Less,
-        Operator::LessEqual,
-        Operator::Greater,
-        Operator::GreaterEqual,
-        Operator::Is,
+        Operator::Equal,       Operator::NotEqual,     Operator::Less,        Operator::LessEqual,
+        Operator::Greater,     Operator::GreaterEqual, Operator::Is,
 
-        Operator::BitAnd,
-        Operator::BitOr,
-        Operator::BitXor,
-        Operator::BitNot,
-        Operator::ShiftLeft,
-        Operator::ShiftRight,
+        Operator::BitAnd,      Operator::BitOr,        Operator::BitXor,      Operator::BitNot,
+        Operator::ShiftLeft,   Operator::ShiftRight,
 
-        Operator::Assign,
-        Operator::PlusAssign,
-        Operator::MinusAssign,
-        Operator::AsteriskAssign,
-        Operator::SlashAssign,
-        Operator::CaretAssign
+        Operator::Assign,      Operator::PlusAssign,   Operator::MinusAssign, Operator::AsteriskAssign,
+        Operator::SlashAssign, Operator::CaretAssign
 
         // Operator::Walrus,
         // Operator::Dot
@@ -352,19 +315,9 @@ namespace Fig::Ast
     {
     public:
         std::vector<Statement> stmts;
-        BlockStatementAst()
-        {
-            type = AstType::BlockStatement;
-        }
-        BlockStatementAst(std::vector<Statement> _stmts) :
-            stmts(std::move(_stmts))
-        {
-            type = AstType::BlockStatement;
-        }
-        virtual FString typeName() override
-        {
-            return FString(u8"BlockStatement");
-        }
+        BlockStatementAst() { type = AstType::BlockStatement; }
+        BlockStatementAst(std::vector<Statement> _stmts) : stmts(std::move(_stmts)) { type = AstType::BlockStatement; }
+        virtual FString typeName() override { return FString(u8"BlockStatement"); }
         virtual FString toString() override
         {
             return FString(std::format("<StmtAst '{}' at {}:{}>", typeName().toBasicString(), aai.line, aai.column));

src/Core/core.hpp

@@ -4,7 +4,7 @@
 #include <cstdint>
 #include <string_view>
 
-#define __FCORE_VERSION "0.4.0-alpha"
+#define __FCORE_VERSION "0.4.2-alpha"
 
 #if defined(_WIN32)
     #define __FCORE_PLATFORM "Windows"

src/Evaluator/Context/context.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include "Ast/Statements/InterfaceDefSt.hpp"
 #include "Value/interface.hpp"
 #include <Value/Type.hpp>
 #include <algorithm>
@@ -303,7 +304,7 @@ namespace Fig
             return false;
         }
 
-        Function getDefaultImplementedMethod(const TypeInfo &structType, const FString &functionName)
+        Ast::InterfaceMethod getDefaultImplementedMethod(const TypeInfo &structType, const FString &functionName)
         {
             // O(N²)
             // SLOW
@@ -336,15 +337,12 @@ namespace Fig
                     if (method.name == functionName)
                     {
                         if (!method.hasDefaultBody()) assert(false);
-
-                        return Function(
-                            method.paras, TypeInfo(method.returnType), method.defaultBody, shared_from_this());
+                        return method;
                     }
                 }
             }
 
             assert(false);
-            return Function(); // ignore warning
         }
 
         const Function &getImplementedMethod(const TypeInfo &structType, const FString &functionName) const

src/Evaluator/Value/IntPool.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "Value/value.hpp"
+#include <Core/fig_string.hpp>
+#include <Value/value_forward.hpp>
+#include <Value/Type.hpp>
+#include <array>
+#include <memory>
+
+namespace Fig
+{
+    class IntPool
+    {
+    private:
+        static constexpr ValueType::IntClass CACHE_MIN = -128;
+        static constexpr ValueType::IntClass CACHE_MAX = 127;
+
+        std::array<ObjectPtr, CACHE_MAX - CACHE_MIN + 1> cache;
+
+    public:
+        IntPool()
+        {
+            for (ValueType::IntClass i = CACHE_MIN; i <= CACHE_MAX; ++i)
+            {
+                cache[i - CACHE_MIN] = std::make_shared<Object>(i);
+            }
+        }
+        ObjectPtr createInt(ValueType::IntClass val) const
+        {
+            if (val >= CACHE_MIN && val <= CACHE_MAX) { return cache[val - CACHE_MIN]; }
+            return std::make_shared<Object>(val);
+        }
+
+        static const IntPool &getInstance()
+        {
+            static IntPool pool;
+            return pool;
+        }
+    };
+}; // namespace Fig

src/Evaluator/Value/LvObject.hpp

@@ -87,7 +87,7 @@ namespace Fig
                             std::format("Variable `{}` expects type `{}`, but got '{}'",
                                         s->name.toBasicString(),
                                         s->declaredType.toString().toBasicString(),
-                                        v->getTypeInfo().toString().toBasicString())));
+                                        prettyType(v).toBasicString())));
                 }
                 if (isAccessConst(s->am))
                 {

src/Evaluator/Value/VariableSlot.hpp

@@ -4,11 +4,12 @@
 #include <Ast/AccessModifier.hpp>
 #include <Core/fig_string.hpp>
 #include <Value/Type.hpp>
+#include <Value/value_forward.hpp>
+
 #include <memory>
 namespace Fig
 {
-    class Object;
-    using ObjectPtr = std::shared_ptr<Object>;
+
     struct VariableSlot
     {
         FString name;

src/Evaluator/Value/value.cpp

@@ -1,3 +1,4 @@
+#include "Value/structType.hpp"
 #include <Value/Type.hpp>
 #include <Value/value.hpp>
 #include <Context/context.hpp>
@@ -26,9 +27,7 @@ namespace Fig
         {
             if (!typeMap.contains(_name))
             {
-                throw RuntimeError(FString(std::format(
-                    "No type named '{}'",
-                    _name.toBasicString())));
+                throw RuntimeError(FString(std::format("No type named '{}'", _name.toBasicString())));
                 // *this = ValueType::String;
             }
             id = typeMap.at(name); // may throw
@@ -41,10 +40,7 @@ namespace Fig
             ObjectPtr value = key.value;
             const TypeInfo &type = value->getTypeInfo();
 
-            if (type == ValueType::Int)
-            {
-                return std::hash<ValueType::IntClass>{}(value->as<ValueType::IntClass>());
-            }
+            if (type == ValueType::Int) { return std::hash<ValueType::IntClass>{}(value->as<ValueType::IntClass>()); }
             if (type == ValueType::Double)
             {
                 return std::hash<ValueType::DoubleClass>{}(value->as<ValueType::DoubleClass>());
@@ -61,10 +57,7 @@ namespace Fig
             {
                 auto HashFields = [](std::vector<Field> fields) {
                     size_t r = 0;
-                    for (auto &f : fields)
-                    {
-                        r += std::hash<Field>{}(f);
-                    }
+                    for (auto &f : fields) { r += std::hash<Field>{}(f); }
                     return r;
                 };
                 const StructType &st = value->as<StructType>();
@@ -73,19 +66,30 @@ namespace Fig
             if (type == ValueType::StructInstance)
             {
                 const StructInstance &si = value->as<StructInstance>();
-                return std::hash<TypeInfo>{}(si.parentType) + std::hash<uint64_t>{}(reinterpret_cast<uint64_t>(std::addressof(*si.localContext)));
+                return std::hash<TypeInfo>{}(si.parentType)
+                       + std::hash<uint64_t>{}(reinterpret_cast<uint64_t>(std::addressof(*si.localContext)));
             }
             assert(false);
             throw ""; // ignore warning
         }
     }
 
-    FString prettyType(std::shared_ptr<const Object> obj)
+    TypeInfo actualType(std::shared_ptr<const Object> obj)
     {
         auto t = obj->getTypeInfo();
-        if (t == ValueType::StructInstance)
-            return obj->as<StructInstance>().parentType.toString();
-        return t.toString();
+        
+        // dispatch builtin struct types (like Int{}, List{} e.g...)
+        if (t == ValueType::StructType)
+        {
+            return obj->as<StructType>().type;
+        }
+
+        if (t == ValueType::StructInstance) return obj->as<StructInstance>().parentType;
+        return t;
+    }
+    FString prettyType(std::shared_ptr<const Object> obj)
+    {
+        return actualType(obj).toString();
     }
 
     const TypeInfo ValueType::Any(FString(u8"Any"), true);                       // id: 1
@@ -102,8 +106,6 @@ namespace Fig
     const TypeInfo ValueType::Module(FString(u8"Module"), true);                 // id: 12
     const TypeInfo ValueType::InterfaceType(FString(u8"InterfaceType"), true);   // id: 13
 
-
-
     bool implements(const TypeInfo &structType, const TypeInfo &interfaceType, ContextPtr ctx)
     {
         return ctx->hasImplRegisted(structType, interfaceType);
@@ -111,28 +113,25 @@ namespace Fig
 
     bool isTypeMatch(const TypeInfo &expected, ObjectPtr obj, ContextPtr ctx)
     {
-        if (expected == ValueType::Any)
-            return true;
+        if (expected == ValueType::Any) return true;
 
         TypeInfo actual = obj->getTypeInfo();
 
-        if (obj->is<StructInstance>())
+        if (obj->is<StructType>())
+        {
+            const StructType &t = obj->as<StructType>();
+            if (expected == t.type) // the StructType typeinfo
+            {
+                return true;
+            }
+        }
+        else if (obj->is<StructInstance>())
         {
             const StructInstance &si = obj->as<StructInstance>();
-            if (si.parentType == expected)
-            {
-                return true;
-            }
-            if (implements(si.parentType, expected, ctx))
-            {
-                return true;
-            }
-            return false;
-        }
-        else
-        {
-            return expected == actual;
+            if (si.parentType == expected) { return true; }
+            if (implements(si.parentType, expected, ctx)) { return true; }
         }
+        return expected == actual;
     }
 
 } // namespace Fig

src/Evaluator/Value/value.hpp

@@ -6,6 +6,7 @@
 #include <Value/Type.hpp>
 #include <Value/valueError.hpp>
 #include <Value/module.hpp>
+#include <Value/value_forward.hpp>
 
 #include <memory>
 #include <variant>
@@ -31,10 +32,8 @@ namespace Fig
             static_cast<ValueType::DoubleClass>(std::numeric_limits<ValueType::IntClass>::min());
         return d > intMaxAsDouble || d < intMinAsDouble;
     }
-    class Object;
-    using ObjectPtr = std::shared_ptr<Object>;
-
 
+    TypeInfo actualType(std::shared_ptr<const Object> obj);
     FString prettyType(std::shared_ptr<const Object> obj);
 
     bool operator==(const Object &, const Object &);
@@ -509,7 +508,7 @@ namespace Fig
             {
                 bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
                 auto result = lhs.getNumericValue() + rhs.getNumericValue();
-                if (bothInt && !isNumberExceededIntLimit(result))
+                if (bothInt)
                     return Object(static_cast<ValueType::IntClass>(result));
                 return Object(result);
             }
@@ -526,7 +525,7 @@ namespace Fig
             {
                 bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
                 auto result = lhs.getNumericValue() - rhs.getNumericValue();
-                if (bothInt && !isNumberExceededIntLimit(result))
+                if (bothInt)
                     return Object(static_cast<ValueType::IntClass>(result));
                 return Object(result);
             }
@@ -541,10 +540,20 @@ namespace Fig
             {
                 bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
                 auto result = lhs.getNumericValue() * rhs.getNumericValue();
-                if (bothInt && !isNumberExceededIntLimit(result))
+                if (bothInt)
                     return Object(static_cast<ValueType::IntClass>(result));
                 return Object(result);
             }
+            if (lhs.is<ValueType::StringClass>() && rhs.is<ValueType::IntClass>())
+            {
+                FString result;
+                const FString &l = lhs.as<ValueType::StringClass>();
+                for (size_t i=0; i < rhs.getNumericValue(); ++i)
+                {
+                    result += l;
+                }
+                return Object(result);
+            }
             throw ValueError(FString(makeTypeErrorMessage("Unsupported operation", "*", lhs, rhs)));
         }
 
@@ -559,7 +568,7 @@ namespace Fig
                     throw ValueError(FString(makeTypeErrorMessage("Division by zero", "/", lhs, rhs)));
                 // bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
                 auto result = lhs.getNumericValue() / rnv;
-                // if (bothInt && !isNumberExceededIntLimit(result))
+                // if (bothInt)
                 //     return Object(static_cast<ValueType::IntClass>(result));
 
                 // int / int maybe decimals
@@ -573,15 +582,24 @@ namespace Fig
         {
             if (lhs.isNull() || rhs.isNull())
                 throw ValueError(FString(makeTypeErrorMessage("Cannot modulo", "%", lhs, rhs)));
+            if (lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>())
+            {
+                ValueType::IntClass lv = lhs.as<ValueType::IntClass>();
+                ValueType::IntClass rv = lhs.as<ValueType::IntClass>();
+                if (rv == 0) throw ValueError(FString(makeTypeErrorMessage("Modulo by zero", "/", lhs, rhs)));
+
+                ValueType::IntClass q = lv / rv;
+                ValueType::IntClass r = lv % rv;
+                if (r != 0 && ((lv < 0) != (rv < 0))) { q -= 1; }
+                return q;
+            }
+            
             if (lhs.isNumeric() && rhs.isNumeric())
             {
                 auto rnv = rhs.getNumericValue();
                 if (rnv == 0)
                     throw ValueError(FString(makeTypeErrorMessage("Modulo by zero", "/", lhs, rhs)));
-                bool bothInt = lhs.is<ValueType::IntClass>() && rhs.is<ValueType::IntClass>();
                 auto result = std::fmod(lhs.getNumericValue(), rnv);
-                if (bothInt && !isNumberExceededIntLimit(result))
-                    return Object(static_cast<ValueType::IntClass>(result));
                 return Object(result);
             }
             throw ValueError(FString(makeTypeErrorMessage("Unsupported operation", "%", lhs, rhs)));
@@ -698,7 +716,7 @@ namespace Fig
             {
                 bool bothInt = base.is<ValueType::IntClass>() && exp.is<ValueType::IntClass>();
                 auto result = std::pow(base.getNumericValue(), exp.getNumericValue());
-                if (bothInt && !isNumberExceededIntLimit(result))
+                if (bothInt)
                     return Object(static_cast<ValueType::IntClass>(result));
                 return Object(result);
             }
@@ -706,7 +724,6 @@ namespace Fig
         }
     };
 
-    using ObjectPtr = std::shared_ptr<Object>;
     using RvObject = ObjectPtr;
 
     inline bool operator==(const ValueKey &l, const ValueKey &r)

src/Evaluator/Value/value_forward.hpp

@@ -0,0 +1,10 @@
+#pragma once
+
+#include <memory>
+
+namespace Fig
+{
+    class Object;
+
+    using ObjectPtr = std::shared_ptr<Object>;
+}; // namespace Fig

src/Evaluator/evaluator.cpp

@@ -1,3 +1,7 @@
+#include <Ast/Expressions/VarExpr.hpp>
+#include <Value/Type.hpp>
+#include <Value/value.hpp>
+#include <Value/IntPool.hpp>
 #include <Ast/Statements/ErrorFlow.hpp>
 #include <Value/VariableSlot.hpp>
 #include <Value/value.hpp>
@@ -120,11 +124,11 @@ namespace Fig
         }
         else if (ctx->hasDefaultImplementedMethod(si.parentType, member))
         {
+            const auto &ifm = ctx->getDefaultImplementedMethod(si.parentType, member);
+            Function fn(ifm.paras, actualType(eval(ifm.returnType, ctx)), ifm.defaultBody, ctx);
+
             return LvObject(std::make_shared<VariableSlot>(
-                                member,
-                                std::make_shared<Object>(ctx->getDefaultImplementedMethod(si.parentType, member)),
-                                ValueType::Function,
-                                AccessModifier::PublicConst),
+                                member, std::make_shared<Object>(fn), ValueType::Function, AccessModifier::PublicConst),
                             ctx);
         }
         else
@@ -222,6 +226,362 @@ namespace Fig
         }
     }
 
+    RvObject Evaluator::evalInitExpr(Ast::InitExpr initExpr, ContextPtr ctx)
+    {
+        LvObject structeLv = evalLv(initExpr->structe, ctx);
+        ObjectPtr structTypeVal = structeLv.get();
+        const FString &structName = structeLv.name();
+        if (!structTypeVal->is<StructType>())
+        {
+            throw EvaluatorError(u8"NotAStructTypeError",
+                                 std::format("'{}' is not a structure type", structName.toBasicString()),
+                                 initExpr);
+        }
+        const StructType &structT = structTypeVal->as<StructType>();
+
+        if (structT.builtin)
+        {
+            const TypeInfo &type = structT.type;
+            auto &args = initExpr->args;
+            size_t argSize = args.size();
+
+            if (argSize > 1)
+            {
+                throw EvaluatorError(u8"StructInitArgumentMismatchError",
+                                     std::format("Builtin class `{}` expects 0 or 1 argument, but {} were provided",
+                                                 type.toString().toBasicString(),
+                                                 argSize),
+                                     initExpr);
+            }
+
+            // default value
+            if (argSize == 0)
+            {
+                if (type == ValueType::Any || type == ValueType::Null || type == ValueType::Function)
+                {
+                    throw EvaluatorError(
+                        u8"BuiltinNotConstructibleError",
+                        std::format("Builtin type `{}` cannot be constructed", type.toString().toBasicString()),
+                        initExpr);
+                }
+                return std::make_shared<Object>(Object::defaultValue(type));
+            }
+
+            ObjectPtr val = eval(args[0].second, ctx);
+
+            auto err = [&](const char *msg) {
+                throw EvaluatorError(u8"BuiltinInitTypeMismatchError",
+                                     std::format("Builtin `{}` constructor {}", type.toString().toBasicString(), msg),
+                                     initExpr);
+            };
+
+            // ===================== Int =====================
+            if (type == ValueType::Int)
+            {
+                if (!val->is<ValueType::IntClass>()) err("expects Int");
+                return std::make_shared<Object>(val->as<ValueType::IntClass>());
+            }
+
+            // ===================== Double =====================
+            if (type == ValueType::Double)
+            {
+                if (!val->is<ValueType::DoubleClass>()) err("expects Double");
+                return std::make_shared<Object>(val->as<ValueType::DoubleClass>());
+            }
+
+            // ===================== Bool =====================
+            if (type == ValueType::Bool)
+            {
+                if (!val->is<ValueType::BoolClass>()) err("expects Bool");
+                return std::make_shared<Object>(val->as<ValueType::BoolClass>());
+            }
+
+            // ===================== String =====================
+            if (type == ValueType::String)
+            {
+                if (!val->is<ValueType::StringClass>()) err("expects String");
+                return std::make_shared<Object>(val->as<ValueType::StringClass>());
+            }
+
+            // ===================== Null =====================
+            if (type == ValueType::Null)
+            {
+                // Null basically ignores input but keep invariant strict:
+                if (!val->is<ValueType::NullClass>()) err("expects Null");
+                return Object::getNullInstance();
+            }
+
+            // ===================== List =====================
+            if (type == ValueType::List)
+            {
+                if (!val->is<List>()) err("expects List");
+
+                const auto &src = val->as<List>();
+                auto copied = std::make_shared<Object>(List{});
+
+                auto &dst = copied->as<List>();
+                dst.reserve(src.size());
+                for (auto &e : src) dst.push_back(e); // shallow element copy, but new container
+
+                return copied;
+            }
+
+            // ===================== Map =====================
+            if (type == ValueType::Map)
+            {
+                if (!val->is<Map>()) err("expects Map");
+
+                const auto &src = val->as<Map>();
+                auto copied = std::make_shared<Object>(Map{});
+
+                auto &dst = copied->as<Map>();
+                for (auto &[k, v] : src) dst.emplace(k, v);
+
+                return copied;
+            }
+
+            throw EvaluatorError(
+                u8"BuiltinNotConstructibleError",
+                std::format("Builtin type `{}` cannot be constructed", type.toString().toBasicString()),
+                initExpr);
+        }
+
+        ContextPtr defContext = structT.defContext; // definition context
+        // check init args
+
+        size_t minArgs = 0;
+        size_t maxArgs = structT.fields.size();
+
+        for (auto &f : structT.fields)
+        {
+            if (f.defaultValue == nullptr) minArgs++;
+        }
+
+        size_t got = initExpr->args.size();
+        if (got > maxArgs || got < minArgs)
+        {
+            throw EvaluatorError(u8"StructInitArgumentMismatchError",
+                                 std::format("Structure '{}' expects {} to {} fields, but {} were provided",
+                                             structName.toBasicString(),
+                                             minArgs,
+                                             maxArgs,
+                                             initExpr->args.size()),
+                                 initExpr);
+        }
+
+        std::vector<std::pair<FString, ObjectPtr>> evaluatedArgs;
+
+        auto evalArguments = [&evaluatedArgs, initExpr, ctx, this]() {
+            for (const auto &[argName, argExpr] : initExpr->args)
+            {
+                evaluatedArgs.push_back({argName, eval(argExpr, ctx)});
+            }
+        };
+
+        ContextPtr instanceCtx =
+            std::make_shared<Context>(FString(std::format("<StructInstance {}>", structName.toBasicString())), ctx);
+        /*
+            3 ways of calling constructor
+            .1 Person {"Fig", 1, "IDK"};
+            .2 Person {name: "Fig", age: 1, sex: "IDK"}; // can be unordered
+            .3 Person {name, age, sex};
+        */
+        {
+            using enum Ast::InitExprAst::InitMode;
+            if (initExpr->initMode == Positional)
+            {
+                evalArguments();
+
+                for (size_t i = 0; i < maxArgs; ++i)
+                {
+                    const Field &field = structT.fields[i];
+                    const FString &fieldName = field.name;
+                    const TypeInfo &expectedType = field.type;
+                    if (i >= evaluatedArgs.size())
+                    {
+                        // we've checked argument count before, so here
+                        // must be a default value
+
+                        // evaluate default value in definition context
+                        ObjectPtr defaultVal = eval(field.defaultValue,
+                                                    ctx); // it can't be null here
+
+                        // type check
+                        if (!isTypeMatch(expectedType, defaultVal, ctx))
+                        {
+                            throw EvaluatorError(
+                                u8"StructFieldTypeMismatchError",
+                                std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
+                                            structName.toBasicString(),
+                                            fieldName.toBasicString(),
+                                            expectedType.toString().toBasicString(),
+                                            prettyType(defaultVal).toBasicString()),
+                                initExpr);
+                        }
+
+                        instanceCtx->def(fieldName, expectedType, field.am, defaultVal);
+                        continue;
+                    }
+
+                    const ObjectPtr &argVal = evaluatedArgs[i].second;
+                    if (!isTypeMatch(expectedType, argVal, ctx))
+                    {
+                        throw EvaluatorError(
+                            u8"StructFieldTypeMismatchError",
+                            std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
+                                        structName.toBasicString(),
+                                        fieldName.toBasicString(),
+                                        expectedType.toString().toBasicString(),
+                                        prettyType(argVal).toBasicString()),
+                            initExpr);
+                    }
+                    instanceCtx->def(fieldName, expectedType, field.am, argVal);
+                }
+            }
+            else if (initExpr->initMode == Named)
+            {
+                evalArguments();
+
+                // named
+                for (size_t i = 0; i < maxArgs; ++i)
+                {
+                    const Field &field = structT.fields[i];
+                    const FString &fieldName = (field.name.empty() ? evaluatedArgs[i].first : field.name);
+                    if (instanceCtx->containsInThisScope(fieldName))
+                    {
+                        throw EvaluatorError(u8"StructFieldRedeclarationError",
+                                             std::format("Field '{}' already initialized in structure '{}'",
+                                                         fieldName.toBasicString(),
+                                                         structName.toBasicString()),
+                                             initExpr);
+                    }
+                    if (i + 1 > got)
+                    {
+                        // use default value                  //
+                        // evaluate default value in definition context
+                        ObjectPtr defaultVal = eval(field.defaultValue,
+                                                    defContext); // it can't be null here
+
+                        // type check
+                        const TypeInfo &expectedType = field.type;
+                        if (!isTypeMatch(expectedType, defaultVal, ctx))
+                        {
+                            throw EvaluatorError(
+                                u8"StructFieldTypeMismatchError",
+                                std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
+                                            structName.toBasicString(),
+                                            fieldName.toBasicString(),
+                                            expectedType.toString().toBasicString(),
+                                            prettyType(defaultVal).toBasicString()),
+                                initExpr);
+                        }
+
+                        instanceCtx->def(fieldName, field.type, field.am, defaultVal);
+                        continue;
+                    }
+                    const ObjectPtr &argVal = evaluatedArgs[i].second;
+                    if (!isTypeMatch(field.type, argVal, ctx))
+                    {
+                        throw EvaluatorError(
+                            u8"StructFieldTypeMismatchError",
+                            std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
+                                        structName.toBasicString(),
+                                        fieldName.toBasicString(),
+                                        field.type.toString().toBasicString(),
+                                        prettyType(argVal).toBasicString()),
+                            initExpr);
+                    }
+                    instanceCtx->def(fieldName, field.type, field.am, argVal);
+                }
+            }
+            else
+            {
+                // shorthand, can be unordered
+                // in this mode, initExpr args are all VarExpr
+                // field name is the variable name
+                for (const auto &[argName, argExpr] : initExpr->args)
+                {
+                    // assert(argExpr->getType() == Ast::AstType::VarExpr);
+                    // argName is var name
+                    const ObjectPtr &argVal = eval(argExpr, ctx); // get the value
+                    // find field
+                    auto fieldIt = std::find_if(
+                        structT.fields.begin(),
+                        structT.fields.end(),
+                        [&argName](const Field &f) { return f.name == argName; });
+                    if (fieldIt == structT.fields.end())
+                    {
+                        throw EvaluatorError(u8"StructFieldNotFoundError",
+                                             std::format("Field '{}' not found in structure '{}'",
+                                                         argName.toBasicString(),
+                                                         structName.toBasicString()),
+                                             initExpr);
+                    }
+                    const Field &field = *fieldIt;
+                    if (!isTypeMatch(field.type, argVal, ctx))
+                    {
+                        throw EvaluatorError(
+                            u8"StructFieldTypeMismatchError",
+                            std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
+                                        structName.toBasicString(),
+                                        field.name.toBasicString(),
+                                        field.type.toString().toBasicString(),
+                                        prettyType(argVal).toBasicString()),
+                            initExpr);
+                    }
+                    // field.name is argName (var name)
+                    // Point{x=x, y=y} --> Point{x, y}
+                
+                    instanceCtx->def(field.name, field.type, field.am, argVal);
+                }
+                // fill default values
+                size_t currentFieldCount = initExpr->args.size(); // we have already check argument count, min <= got <= max
+                // so remain fields start from currentFieldCount to maxArgs
+                for (size_t i = currentFieldCount; i < maxArgs; ++i)
+                {
+                    const Field &field = structT.fields[i];
+
+                    // evaluate default value in definition context
+                    ObjectPtr defaultVal = eval(field.defaultValue,
+                                                defContext); // it can't be null here
+
+                    // type check
+                    if (!isTypeMatch(field.type, defaultVal, ctx))
+                    {
+                        throw EvaluatorError(
+                            u8"StructFieldTypeMismatchError",
+                            std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
+                                        structName.toBasicString(),
+                                        field.name.toBasicString(),
+                                        field.type.toString().toBasicString(),
+                                        prettyType(defaultVal).toBasicString()),
+                            initExpr);
+                    }
+
+                    instanceCtx->def(field.name, field.type, field.am, defaultVal);
+                }
+            }
+        }
+        ContextPtr stDefCtx = structT.defContext;
+
+        // load struct method
+        for (auto &[id, fn] : stDefCtx->getFunctions())
+        {
+            auto funcNameOpt = stDefCtx->getFunctionName(id);
+            assert(funcNameOpt.has_value());
+
+            const FString &funcName = *funcNameOpt;
+            auto funcSlot = stDefCtx->get(funcName);
+
+            instanceCtx->def(funcName,
+                             ValueType::Function,
+                             funcSlot->am,
+                             std::make_shared<Object>(Function(fn.paras, fn.retType, fn.body, instanceCtx)));
+        }
+
+        return std::make_shared<Object>(StructInstance(structT.type, instanceCtx));
+    }
+
     RvObject Evaluator::evalBinary(Ast::BinaryExpr bin, ContextPtr ctx)
     {
         using Ast::Operator;
@@ -232,16 +592,37 @@ namespace Fig
             case Operator::Add: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() + rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
+
                 return std::make_shared<Object>(*lhs + *rhs);
             }
             case Operator::Subtract: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() - rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
+
                 return std::make_shared<Object>(*lhs - *rhs);
             };
             case Operator::Multiply: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() * rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
+
                 return std::make_shared<Object>((*lhs) * (*rhs));
             };
             case Operator::Divide: {
@@ -252,11 +633,40 @@ namespace Fig
             case Operator::Modulo: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass lv = lhs->as<ValueType::IntClass>();
+                    ValueType::IntClass rv = lhs->as<ValueType::IntClass>();
+                    if (rv == 0)
+                    {
+                        throw ValueError(
+                            FString(
+                                std::format(
+                                    "Modulo by zero: {} % {}",
+                                    lv,
+                                    rv
+                                )
+                            )
+                        );
+                    }
+                    ValueType::IntClass result = lv / rv;
+                    ValueType::IntClass r = lv % rv;
+                    if (r != 0 && ((lv < 0) != (rv < 0))) { result -= 1; }
+                    return IntPool::getInstance().createInt(result);
+                }
+
                 return std::make_shared<Object>(*lhs % *rhs);
             };
             case Operator::Power: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = std::pow(lhs->as<ValueType::IntClass>(),rhs->as<ValueType::IntClass>());
+                    return IntPool::getInstance().createInt(result);
+                }
                 return std::make_shared<Object>(power(*lhs, *rhs));
             }
             case Operator::And: {
@@ -343,34 +753,64 @@ namespace Fig
 
                 throw EvaluatorError(u8"TypeError",
                                      std::format("Unsupported operator `is` for '{}' && '{}'",
-                                                 lhsType.toString().toBasicString(),
-                                                 rhsType.toString().toBasicString()),
+                                                 prettyType(lhs).toBasicString(),
+                                                 prettyType(rhs).toBasicString()),
                                      bin->lexp);
             }
 
             case Operator::BitAnd: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() & rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
                 return std::make_shared<Object>(bit_and(*lhs, *rhs));
             }
             case Operator::BitOr: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() | rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
                 return std::make_shared<Object>(bit_or(*lhs, *rhs));
             }
             case Operator::BitXor: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() ^ rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
                 return std::make_shared<Object>(bit_xor(*lhs, *rhs));
             }
             case Operator::ShiftLeft: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() << rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
                 return std::make_shared<Object>(shift_left(*lhs, *rhs));
             }
             case Operator::ShiftRight: {
                 ObjectPtr lhs = eval(lexp, ctx);
                 ObjectPtr rhs = eval(rexp, ctx);
+
+                if (lhs->is<ValueType::IntClass>() && rhs->is<ValueType::IntClass>())
+                {
+                    ValueType::IntClass result = lhs->as<ValueType::IntClass>() >> rhs->as<ValueType::IntClass>();
+                    return IntPool::getInstance().createInt(result);
+                }
                 return std::make_shared<Object>(shift_right(*lhs, *rhs));
             }
 
@@ -439,7 +879,6 @@ namespace Fig
             case Operator::BitNot: {
                 return std::make_shared<Object>(bit_not((*value)));
             }
-
             default: {
                 throw EvaluatorError(u8"UnsupportedOpError",
                                      std::format("Unsupported op '{}' for unary expression", magic_enum::enum_name(op)),
@@ -721,281 +1160,8 @@ namespace Fig
             }
             case AstType::InitExpr: {
                 auto initExpr = std::static_pointer_cast<Ast::InitExprAst>(exp);
-                LvObject structeLv = evalLv(initExpr->structe, ctx);
-                ObjectPtr structTypeVal = structeLv.get();
-                const FString &structName = structeLv.name();
-                if (!structTypeVal->is<StructType>())
-                {
-                    throw EvaluatorError(u8"NotAStructTypeError",
-                                         std::format("'{}' is not a structure type", structName.toBasicString()),
-                                         initExpr);
-                }
-                const StructType &structT = structTypeVal->as<StructType>();
-
-                if (structT.builtin)
-                {
-                    const TypeInfo &type = structT.type;
-                    auto &args = initExpr->args;
-                    size_t argSize = args.size();
-
-                    if (argSize > 1)
-                    {
-                        throw EvaluatorError(
-                            u8"StructInitArgumentMismatchError",
-                            std::format("Builtin class `{}` expects 0 or 1 argument, but {} were provided",
-                                        type.toString().toBasicString(),
-                                        argSize),
-                            initExpr);
-                    }
-
-                    // default value
-                    if (argSize == 0)
-                    {
-                        if (type == ValueType::Any || type == ValueType::Null || type == ValueType::Function)
-                        {
-                            throw EvaluatorError(
-                                u8"BuiltinNotConstructibleError",
-                                std::format("Builtin type `{}` cannot be constructed", type.toString().toBasicString()),
-                                initExpr);
-                        }
-                        return std::make_shared<Object>(Object::defaultValue(type));
-                    }
-
-                    ObjectPtr val = eval(args[0].second, ctx);
-
-                    auto err = [&](const char *msg) {
-                        throw EvaluatorError(
-                            u8"BuiltinInitTypeMismatchError",
-                            std::format("Builtin `{}` constructor {}", type.toString().toBasicString(), msg),
-                            initExpr);
-                    };
-
-                    // ===================== Int =====================
-                    if (type == ValueType::Int)
-                    {
-                        if (!val->is<ValueType::IntClass>()) err("expects Int");
-                        return std::make_shared<Object>(val->as<ValueType::IntClass>());
-                    }
-
-                    // ===================== Double =====================
-                    if (type == ValueType::Double)
-                    {
-                        if (!val->is<ValueType::DoubleClass>()) err("expects Double");
-                        return std::make_shared<Object>(val->as<ValueType::DoubleClass>());
-                    }
-
-                    // ===================== Bool =====================
-                    if (type == ValueType::Bool)
-                    {
-                        if (!val->is<ValueType::BoolClass>()) err("expects Bool");
-                        return std::make_shared<Object>(val->as<ValueType::BoolClass>());
-                    }
-
-                    // ===================== String =====================
-                    if (type == ValueType::String)
-                    {
-                        if (!val->is<ValueType::StringClass>()) err("expects String");
-                        return std::make_shared<Object>(val->as<ValueType::StringClass>());
-                    }
-
-                    // ===================== Null =====================
-                    if (type == ValueType::Null)
-                    {
-                        // Null basically ignores input but keep invariant strict:
-                        if (!val->is<ValueType::NullClass>()) err("expects Null");
-                        return Object::getNullInstance();
-                    }
-
-                    // ===================== List =====================
-                    if (type == ValueType::List)
-                    {
-                        if (!val->is<List>()) err("expects List");
-
-                        const auto &src = val->as<List>();
-                        auto copied = std::make_shared<Object>(List{});
-
-                        auto &dst = copied->as<List>();
-                        dst.reserve(src.size());
-                        for (auto &e : src) dst.push_back(e); // shallow element copy, but new container
-
-                        return copied;
-                    }
-
-                    // ===================== Map =====================
-                    if (type == ValueType::Map)
-                    {
-                        if (!val->is<Map>()) err("expects Map");
-
-                        const auto &src = val->as<Map>();
-                        auto copied = std::make_shared<Object>(Map{});
-
-                        auto &dst = copied->as<Map>();
-                        for (auto &[k, v] : src) dst.emplace(k, v);
-
-                        return copied;
-                    }
-
-                    throw EvaluatorError(
-                        u8"BuiltinNotConstructibleError",
-                        std::format("Builtin type `{}` cannot be constructed", type.toString().toBasicString()),
-                        initExpr);
-                }
-
-                ContextPtr defContext = structT.defContext; // definition context
-                // check init args
-
-                size_t minArgs = 0;
-                size_t maxArgs = structT.fields.size();
-
-                for (auto &f : structT.fields)
-                {
-                    if (f.defaultValue == nullptr) minArgs++;
-                }
-
-                size_t got = initExpr->args.size();
-                if (got > maxArgs || got < minArgs)
-                {
-                    throw EvaluatorError(u8"StructInitArgumentMismatchError",
-                                         std::format("Structure '{}' expects {} to {} fields, but {} were provided",
-                                                     structName.toBasicString(),
-                                                     minArgs,
-                                                     maxArgs,
-                                                     initExpr->args.size()),
-                                         initExpr);
-                }
-
-                std::vector<std::pair<FString, ObjectPtr>> evaluatedArgs;
-                for (const auto &[argName, argExpr] : initExpr->args)
-                {
-                    evaluatedArgs.push_back({argName, eval(argExpr, ctx)});
-                }
-                ContextPtr instanceCtx = std::make_shared<Context>(
-                    FString(std::format("<StructInstance {}>", structName.toBasicString())), ctx);
-                /*
-                    3 ways of calling constructor
-                    .1 Person {"Fig", 1, "IDK"};
-                    .2 Person {name: "Fig", age: 1, sex: "IDK"}; // can be unordered
-                    .3 Person {name, age, sex};
-                */
-                {
-                    using enum Ast::InitExprAst::InitMode;
-                    if (initExpr->initMode == Positional)
-                    {
-                        for (size_t i = 0; i < maxArgs; ++i)
-                        {
-                            const Field &field = structT.fields[i];
-                            const FString &fieldName = field.name;
-                            const TypeInfo &expectedType = field.type;
-                            if (i >= evaluatedArgs.size())
-                            {
-                                // we've checked argument count before, so here
-                                // must be a default value
-
-                                // evaluate default value in definition context
-                                ObjectPtr defaultVal = eval(field.defaultValue,
-                                                            ctx); // it can't be null here
-
-                                // type check
-                                if (!isTypeMatch(expectedType, defaultVal, ctx))
-                                {
-                                    throw EvaluatorError(
-                                        u8"StructFieldTypeMismatchError",
-                                        std::format(
-                                            "In structure '{}', field '{}' expects type '{}', but got type '{}'",
-                                            structName.toBasicString(),
-                                            fieldName.toBasicString(),
-                                            expectedType.toString().toBasicString(),
-                                            prettyType(defaultVal).toBasicString()),
-                                        initExpr);
-                                }
-
-                                instanceCtx->def(fieldName, expectedType, field.am, defaultVal);
-                                continue;
-                            }
-
-                            const ObjectPtr &argVal = evaluatedArgs[i].second;
-                            if (!isTypeMatch(expectedType, argVal, ctx))
-                            {
-                                throw EvaluatorError(
-                                    u8"StructFieldTypeMismatchError",
-                                    std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
-                                                structName.toBasicString(),
-                                                fieldName.toBasicString(),
-                                                expectedType.toString().toBasicString(),
-                                                prettyType(argVal).toBasicString()),
-                                    initExpr);
-                            }
-                            instanceCtx->def(fieldName, expectedType, field.am, argVal);
-                        }
-                    }
-                    else
-                    {
-                        // named / shorthand init
-                        for (size_t i = 0; i < maxArgs; ++i)
-                        {
-                            const Field &field = structT.fields[i];
-                            const FString &fieldName = (field.name.empty() ? evaluatedArgs[i].first : field.name);
-                            if (instanceCtx->containsInThisScope(fieldName))
-                            {
-                                throw EvaluatorError(u8"StructFieldRedeclarationError",
-                                                     std::format("Field '{}' already initialized in structure '{}'",
-                                                                 fieldName.toBasicString(),
-                                                                 structName.toBasicString()),
-                                                     initExpr);
-                            }
-                            if (i + 1 > got)
-                            {
-                                // use default value                  //
-                                // evaluate default value in definition context
-                                ObjectPtr defaultVal = eval(field.defaultValue,
-                                                            defContext); // it can't be null here
-
-                                // type check
-                                const TypeInfo &expectedType = field.type;
-                                if (!isTypeMatch(expectedType, defaultVal, ctx))
-                                {
-                                    throw EvaluatorError(
-                                        u8"StructFieldTypeMismatchError",
-                                        std::format(
-                                            "In structure '{}', field '{}' expects type '{}', but got type '{}'",
-                                            structName.toBasicString(),
-                                            fieldName.toBasicString(),
-                                            expectedType.toString().toBasicString(),
-                                            prettyType(defaultVal).toBasicString()),
-                                        initExpr);
-                                }
-
-                                instanceCtx->def(fieldName, field.type, field.am, defaultVal);
-                                continue;
-                            }
-                            const ObjectPtr &argVal = evaluatedArgs[i].second;
-                            if (!isTypeMatch(field.type, argVal, ctx))
-                            {
-                                throw EvaluatorError(
-                                    u8"StructFieldTypeMismatchError",
-                                    std::format("In structure '{}', field '{}' expects type '{}', but got type '{}'",
-                                                structName.toBasicString(),
-                                                fieldName.toBasicString(),
-                                                field.type.toString().toBasicString(),
-                                                prettyType(argVal).toBasicString()),
-                                    initExpr);
-                            }
-                            instanceCtx->def(fieldName, field.type, field.am, argVal);
-                        }
-                    }
-                }
-                instanceCtx->merge(*structT.defContext);
-                for (auto &[id, fn] : instanceCtx->getFunctions())
-                {
-                    instanceCtx->_update(*instanceCtx->getFunctionName(id),
-                                         std::make_shared<Object>(Function(fn.paras,
-                                                                           fn.retType,
-                                                                           fn.body,
-                                                                           instanceCtx) // change its closureContext to
-                                                                                        // struct instance's context
-                                                                  ));
-                }
-                return std::make_shared<Object>(StructInstance(structT.type, instanceCtx));
+                assert(initExpr != nullptr);
+                return evalInitExpr(initExpr, ctx);
             }
 
             case AstType::ListExpr: {
@@ -1056,18 +1222,22 @@ namespace Fig
 
                 RvObject value = nullptr;
                 if (varDef->expr) { value = eval(varDef->expr, ctx); }
+
                 TypeInfo declaredType; // default is Any
-                const FString &declaredTypeName = varDef->typeName;
-                if (declaredTypeName == Parser::varDefTypeFollowed) { declaredType = value->getTypeInfo(); }
-                else if (!declaredTypeName.empty())
+                const Ast::Expression &declaredTypeExp = varDef->declaredType;
+
+                if (varDef->followupType) { declaredType = actualType(value); }
+                else if (declaredTypeExp)
                 {
-                    declaredType = TypeInfo(declaredTypeName);
+                    ObjectPtr declaredTypeValue = eval(declaredTypeExp, ctx);
+                    declaredType = actualType(declaredTypeValue);
+
                     if (value != nullptr && !isTypeMatch(declaredType, value, ctx))
                     {
                         throw EvaluatorError(u8"TypeError",
                                              std::format("Variable `{}` expects init-value type `{}`, but got '{}'",
                                                          varDef->name.toBasicString(),
-                                                         declaredTypeName.toBasicString(),
+                                                         prettyType(declaredTypeValue).toBasicString(),
                                                          prettyType(value).toBasicString()),
                                              varDef->expr);
                     }
@@ -1095,7 +1265,14 @@ namespace Fig
                         std::format("Function `{}` already declared in this scope", fnName.toBasicString()),
                         fnDef);
                 }
-                Function fn(fnDef->paras, TypeInfo(fnDef->retType), fnDef->body, ctx);
+                TypeInfo returnType = ValueType::Any;
+                if (fnDef->retType)
+                {
+                    ObjectPtr returnTypeValue = eval(fnDef->retType, ctx);
+                    returnType = actualType(returnTypeValue);
+                }
+
+                Function fn(fnDef->paras, returnType, fnDef->body, ctx);
                 ctx->def(fnName,
                          ValueType::Function,
                          (fnDef->isPublic ? AccessModifier::PublicConst : AccessModifier::Const),
@@ -1126,7 +1303,14 @@ namespace Fig
                                                          stDef->name.toBasicString()),
                                              stDef);
                     }
-                    fields.push_back(Field(field.am, field.fieldName, TypeInfo(field.tiName), field.defaultValueExpr));
+                    TypeInfo fieldType = ValueType::Any;
+                    if (field.declaredType)
+                    {
+                        ObjectPtr declaredTypeValue = eval(field.declaredType, ctx);
+                        fieldType = actualType(declaredTypeValue);
+                    }
+
+                    fields.push_back(Field(field.am, field.fieldName, fieldType, field.defaultValueExpr));
                 }
                 ContextPtr defContext = std::make_shared<Context>(FString(std::format("<Struct {} at {}:{}>",
                                                                                       stDef->name.toBasicString(),
@@ -1297,8 +1481,10 @@ namespace Fig
 
                     implemented.insert(name);
 
+                    ObjectPtr returnTypeValue = eval(ifMethod.returnType, ctx);
+
                     record.implMethods[name] =
-                        Function(implMethod.paras, TypeInfo(ifMethod.returnType), implMethod.body, ctx);
+                        Function(implMethod.paras, actualType(returnTypeValue), implMethod.body, ctx);
                 }
 
                 for (auto &m : interface.methods)
@@ -1474,13 +1660,11 @@ namespace Fig
             case BreakSt: {
                 if (!ctx->parent)
                 {
-                    throw EvaluatorError(
-                        u8"BreakOutsideLoopError", u8"`break` statement outside loop", stmt);
+                    throw EvaluatorError(u8"BreakOutsideLoopError", u8"`break` statement outside loop", stmt);
                 }
                 if (!ctx->isInLoopContext())
                 {
-                    throw EvaluatorError(
-                        u8"BreakOutsideLoopError", u8"`break` statement outside loop", stmt);
+                    throw EvaluatorError(u8"BreakOutsideLoopError", u8"`break` statement outside loop", stmt);
                 }
                 return StatementResult::breakFlow();
             }
@@ -1488,13 +1672,11 @@ namespace Fig
             case ContinueSt: {
                 if (!ctx->parent)
                 {
-                    throw EvaluatorError(
-                        u8"ContinueOutsideLoopError", u8"`continue` statement outside loop", stmt);
+                    throw EvaluatorError(u8"ContinueOutsideLoopError", u8"`continue` statement outside loop", stmt);
                 }
                 if (!ctx->isInLoopContext())
                 {
-                    throw EvaluatorError(
-                        u8"ContinueOutsideLoopError", u8"`continue` statement outside loop", stmt);
+                    throw EvaluatorError(u8"ContinueOutsideLoopError", u8"`continue` statement outside loop", stmt);
                 }
                 return StatementResult::continueFlow();
             }
@@ -1506,6 +1688,15 @@ namespace Fig
                 return StatementResult::normal(eval(exprStmt->exp, ctx));
             }
 
+            case BlockStatement: {
+                auto block = std::static_pointer_cast<Ast::BlockStatementAst>(stmt);
+                assert(block != nullptr);
+
+                ContextPtr blockCtx = std::make_shared<Context>(
+                    FString(std::format("<Block at {}:{}>", block->getAAI().line, block->getAAI().column)), ctx);
+                return evalBlockStatement(block, blockCtx);
+            }
+
             default:
                 throw RuntimeError(
                     FString(std::format("Feature stmt {} unsupported yet", magic_enum::enum_name(stmt->getType()))));
@@ -1665,9 +1856,8 @@ namespace Fig
 
         if (ctx->containsInThisScope(modName))
         {
-            throw EvaluatorError(u8"RedeclarationError",
-                                 std::format("{} has already been declared.", modName.toBasicString()),
-                                 i);
+            throw EvaluatorError(
+                u8"RedeclarationError", std::format("{} has already been declared.", modName.toBasicString()), i);
         }
         ctx->def(
             modName, ValueType::Module, AccessModifier::PublicConst, std::make_shared<Object>(Module(modName, modCtx)));

src/Evaluator/evaluator.hpp

@@ -1,3 +1,4 @@
+#include "Ast/Expressions/InitExpr.hpp"
 #include <Ast/Statements/ImplementSt.hpp>
 #include <Ast/Statements/InterfaceDefSt.hpp>
 #include <Value/Type.hpp>
@@ -127,7 +128,7 @@ namespace Fig
         LvObject evalLv(Ast::Expression, ContextPtr); // for access: a.b / index a[b]
 
         /* Right-value eval*/
-
+        RvObject evalInitExpr(Ast::InitExpr, ContextPtr); // only allows evalUnary to call
         RvObject evalBinary(Ast::BinaryExpr, ContextPtr);   // normal binary expr: +, -, *....
         RvObject evalUnary(Ast::UnaryExpr, ContextPtr);     // unary expr
         RvObject evalTernary(Ast::TernaryExpr, ContextPtr); // ternary expr

src/Lexer/lexer.cpp

@@ -66,7 +66,10 @@ namespace Fig
         {FString(u8"["), TokenType::LeftBracket},
         {FString(u8"]"), TokenType::RightBracket},
         {FString(u8"{"), TokenType::LeftBrace},
-        {FString(u8"}"), TokenType::RightBrace}};
+        {FString(u8"}"), TokenType::RightBrace},
+        {FString(u8"?"), TokenType::Question},
+        {FString(u8"!"), TokenType::Not},
+    };
 
     const std::unordered_map<FString, TokenType> Lexer::keyword_map{
         {FString(u8"and"), TokenType::And},
@@ -81,6 +84,7 @@ namespace Fig
         {FString(u8"for"), TokenType::For},
         {FString(u8"if"), TokenType::If},
         {FString(u8"else"), TokenType::Else},
+        {FString(u8"new"), TokenType::New},
         {FString(u8"struct"), TokenType::Struct},
         {FString(u8"interface"), TokenType::Interface},
         {FString(u8"impl"), TokenType::Implement},

src/Module/Library/std/formater/formater.fig

@@ -33,14 +33,14 @@ public func format(objects ...) -> Any
 {
     if objects.length() < 1
     {
-        throw FormatError{"Require format string"};
+        throw new FormatError{"Require format string"};
     }
 
     var fmt := objects[0];
     var fmtType := value.type(fmt);
     if fmtType != "String"
     {
-        throw FormatError{"arg 0 (fmt) must be String type, got " + fmtType};
+        throw new FormatError{"arg 0 (fmt) must be String type, got " + fmtType};
     }
 
     var result := "";
@@ -56,7 +56,7 @@ public func format(objects ...) -> Any
         {
             if (i + 1 >= length)
             {
-                throw FormatError{"unclosed brace"};
+                throw new FormatError{"unclosed brace"};
             }
             
             var nextChar = fmt[i + 1];
@@ -80,12 +80,12 @@ public func format(objects ...) -> Any
             
             if endIndex == -1
             {
-                throw FormatError{"unclosed brace"};
+                throw new FormatError{"unclosed brace"};
             }
             
             if argIndex >= objects.length()
             {
-                throw FormatError{"require enough format expression"};
+                throw new FormatError{"require enough format expression"};
             }
             
             result += value.string_from(objects[argIndex]);
@@ -102,7 +102,7 @@ public func format(objects ...) -> Any
                 continue;
             }
             
-            throw FormatError{"invalid format syntax"};
+            throw new FormatError{"invalid format syntax"};
         }
         else
         {
@@ -122,14 +122,14 @@ public func formatByListArgs(objects) -> Any
     }
 if objects.length() < 1
     {
-        throw FormatError{"Require format string"};
+        throw new FormatError{"Require format string"};
     }
 
     var fmt := objects[0];
     var fmtType := value.type(fmt);
     if fmtType != "String"
     {
-        throw FormatError{"arg 0 (fmt) must be String type, got " + fmtType};
+        throw new FormatError{"arg 0 (fmt) must be String type, got " + fmtType};
     }
 
     var result := "";
@@ -145,7 +145,7 @@ if objects.length() < 1
         {
             if (i + 1 >= length)
             {
-                throw FormatError{"unclosed brace"};
+                throw new FormatError{"unclosed brace"};
             }
             
             var nextChar = fmt[i + 1];
@@ -169,12 +169,12 @@ if objects.length() < 1
             
             if endIndex == -1
             {
-                throw FormatError{"unclosed brace"};
+                throw new FormatError{"unclosed brace"};
             }
             
             if argIndex >= objects.length()
             {
-                throw FormatError{"require enough format expression"};
+                throw new FormatError{"require enough format expression"};
             }
             
             result += value.string_from(objects[argIndex]);
@@ -191,7 +191,7 @@ if objects.length() < 1
                 continue;
             }
             
-            throw FormatError{"invalid format syntax"};
+            throw new FormatError{"invalid format syntax"};
         }
         else
         {

src/Module/Library/std/time/time.fig

@@ -47,5 +47,5 @@ public struct Time
 
 public func now() -> Time
 {
-    return Time{__ftime_now_ns()};
+    return new Time{__ftime_now_ns()};
 }

src/Module/builtins.hpp

@@ -1,5 +1,8 @@
 #pragma once
 
+#include "Ast/Expressions/VarExpr.hpp"
+#include "Ast/Statements/VarDef.hpp"
+#include "Ast/astBase.hpp"
 #include <Ast/Statements/InterfaceDefSt.hpp>
 #include <Ast/functionParameters.hpp>
 #include <Core/fig_string.hpp>
@@ -35,11 +38,19 @@ namespace Fig
             {u8"true", Object::getTrueInstance()},
             {u8"false", Object::getFalseInstance()},
             {u8"Error",
-             std::make_shared<Object>(InterfaceType(
-                 ErrorInterfaceTypeInfo,
-                 {Ast::InterfaceMethod(u8"toString", Ast::FunctionParameters({}, {}), u8"String", nullptr),
-                  Ast::InterfaceMethod(u8"getErrorClass", Ast::FunctionParameters({}, {}), u8"String", nullptr),
-                  Ast::InterfaceMethod(u8"getErrorMessage", Ast::FunctionParameters({}, {}), u8"String", nullptr)}))},
+             std::make_shared<Object>(InterfaceType(ErrorInterfaceTypeInfo,
+                                                    {Ast::InterfaceMethod(u8"toString",
+                                                                          Ast::FunctionParameters({}, {}),
+                                                                          std::make_shared<Ast::VarExprAst>(u8"String"),
+                                                                          nullptr),
+                                                     Ast::InterfaceMethod(u8"getErrorClass",
+                                                                          Ast::FunctionParameters({}, {}),
+                                                                          std::make_shared<Ast::VarExprAst>(u8"String"),
+                                                                          nullptr),
+                                                     Ast::InterfaceMethod(u8"getErrorMessage",
+                                                                          Ast::FunctionParameters({}, {}),
+                                                                          std::make_shared<Ast::VarExprAst>(u8"String"),
+                                                                          nullptr)}))},
 
             {u8"Any", std::make_shared<Object>(StructType(ValueType::Any, nullptr, {}, true))},
             {u8"Int", std::make_shared<Object>(StructType(ValueType::Int, nullptr, {}, true))},

src/Parser/parser.cpp

@@ -1,9 +1,9 @@
-#include "Ast/Statements/ErrorFlow.hpp"
-#include "Ast/Statements/ImplementSt.hpp"
-#include "Ast/astBase.hpp"
-#include "Ast/functionParameters.hpp"
-#include "Error/error.hpp"
-#include "Token/token.hpp"
+#include <Ast/Statements/ErrorFlow.hpp>
+#include <Ast/Statements/ImplementSt.hpp>
+#include <Ast/astBase.hpp>
+#include <Ast/functionParameters.hpp>
+#include <Error/error.hpp>
+#include <Token/token.hpp>
 #include <Parser/parser.hpp>
 
 namespace Fig
@@ -54,17 +54,17 @@ namespace Fig
 
         // // 点运算符
         // {Ast::Operator::Dot, {40, 41}},
+        {Ast::Operator::TernaryCond, {3, 2}},
     };
 
     const std::unordered_map<Ast::Operator, Parser::Precedence> Parser::unaryOpPrecedence = {
         {Ast::Operator::Subtract, 150}, // -
-        {Ast::Operator::BitAnd, 150}, // &
-        {Ast::Operator::BitNot, 150}, // ~
-        {Ast::Operator::Not, 150}, // !
+        {Ast::Operator::BitAnd, 150},   // &
+        {Ast::Operator::BitNot, 150},   // ~
+        {Ast::Operator::Not, 150},      // !
     };
 
-        Ast::VarDef
-        Parser::__parseVarDef(bool isPublic)
+    Ast::VarDef Parser::__parseVarDef(bool isPublic)
     {
         // entry: current is keyword `var` or `const`
         bool isConst = (currentToken().getType() == TokenType::Const ? true : false);
@@ -72,31 +72,31 @@ namespace Fig
         expect(TokenType::Identifier);
         FString name = currentToken().getValue();
         next();
-        FString tiName = ValueType::Any.name;
+        Ast::Expression declaredType = nullptr;
         bool hasSpecificType = false;
         if (isThis(TokenType::Colon)) // :
         {
-            expectPeek(TokenType::Identifier, FString(u8"Type name"));
-            next();
-            tiName = currentToken().getValue();
-            next();
+            next(); // consume `:`
+            declaredType = parseExpression(0, TokenType::Assign, TokenType::Semicolon);
             hasSpecificType = true;
         }
         if (isThis(TokenType::Semicolon))
         {
             next(); // consume `;`, no using expectConsume here cause we don't need to check again
-            return makeAst<Ast::VarDefAst>(isPublic, isConst, name, tiName, nullptr);
+            return makeAst<Ast::VarDefAst>(isPublic, isConst, name, declaredType, nullptr, false);
         }
         if (!isThis(TokenType::Assign) and !isThis(TokenType::Walrus)) expect(TokenType::Assign, u8"assign or walrus");
+        bool followupType = false;
+
         if (isThis(TokenType::Walrus))
         {
             if (hasSpecificType) throwAddressableError<SyntaxError>(FString(u8""));
-            tiName = Parser::varDefTypeFollowed;
+            followupType = true;
         }
         next();
         Ast::Expression exp = parseExpression(0);
         expectSemicolon();
-        return makeAst<Ast::VarDefAst>(isPublic, isConst, name, tiName, exp);
+        return makeAst<Ast::VarDefAst>(isPublic, isConst, name, declaredType, exp, followupType);
     }
 
     ObjectPtr Parser::__parseValue()
@@ -133,18 +133,12 @@ namespace Fig
                 return std::make_shared<Object>(i);
             }
         }
-        else if (currentToken().getType() == TokenType::LiteralString)
-        {
-            return std::make_shared<Object>(_val);
-        }
+        else if (currentToken().getType() == TokenType::LiteralString) { return std::make_shared<Object>(_val); }
         else if (currentToken().getType() == TokenType::LiteralBool)
         {
             return std::make_shared<Object>((_val == u8"true" ? true : false));
         }
-        else if (currentToken().getType() == TokenType::LiteralNull)
-        {
-            return Object::getNullInstance();
-        }
+        else if (currentToken().getType() == TokenType::LiteralNull) { return Object::getNullInstance(); }
         else
         {
             throw std::runtime_error(std::string("Internal Error at: ") + std::string(__func__));
@@ -237,17 +231,17 @@ namespace Fig
         next();
         expect(TokenType::LeftParen);
         Ast::FunctionParameters params = __parseFunctionParameters();
-        FString retTiName = ValueType::Any.name;
+
+        Ast::Expression returnType;
+
         if (isThis(TokenType::RightArrow)) // ->
         {
             next(); // skip `->`
-            expect(TokenType::Identifier);
-            retTiName = currentToken().getValue();
-            next(); // skip return type
+            returnType = parseExpression(0, TokenType::LeftBrace, TokenType::Semicolon);
         }
         expect(TokenType::LeftBrace);
         Ast::BlockStatement body = __parseBlockStatement();
-        return makeAst<Ast::FunctionDefSt>(funcName, params, isPublic, retTiName, body);
+        return makeAst<Ast::FunctionDefSt>(funcName, params, isPublic, returnType, body);
     }
     Ast::StructDef Parser::__parseStructDef(bool isPublic)
     {
@@ -289,13 +283,11 @@ namespace Fig
             {
                 throwAddressableError<SyntaxError>(FString(std::format("expect field name or field attribute")));
             }
-            FString tiName = ValueType::Any.name;
+            Ast::Expression fieldType = nullptr;
             if (isThis(TokenType::Colon))
             {
-                next();
-                expect(TokenType::Identifier, u8"type name");
-                tiName = currentToken().getValue();
-                next();
+                next(); // consume `:`
+                fieldType = parseExpression(0, TokenType::Assign, TokenType::Semicolon);
             }
             Ast::Expression initExpr = nullptr;
             if (isThis(TokenType::Assign))
@@ -305,7 +297,7 @@ namespace Fig
                 initExpr = parseExpression(0);
             }
             expectSemicolon();
-            return Ast::StructDefField(am, fieldName, tiName, initExpr);
+            return Ast::StructDefField(am, fieldName, fieldType, initExpr);
         };
         std::vector<Ast::Statement> stmts;
         std::vector<Ast::StructDefField> fields;
@@ -318,10 +310,7 @@ namespace Fig
                 next(); // consume `}`
                 break;
             }
-            if (isThis(TokenType::Identifier))
-            {
-                fields.push_back(__parseStructField(false));
-            }
+            if (isThis(TokenType::Identifier)) { fields.push_back(__parseStructField(false)); }
             else if (isThis(TokenType::Public))
             {
                 if (isNext(TokenType::Const))
@@ -361,23 +350,18 @@ namespace Fig
                 next(); // consume `struct`
                 stmts.push_back(__parseStructDef(false));
             }
-            else if (isThis(TokenType::Const))
-            {
-                fields.push_back(__parseStructField(false));
-            }
+            else if (isThis(TokenType::Const)) { fields.push_back(__parseStructField(false)); }
             else if (isThis(TokenType::Variable))
             {
-                throwAddressableError<SyntaxError>(FString("Variables are not allowed to be defined within a structure."));
+                throwAddressableError<SyntaxError>(
+                    FString("Variables are not allowed to be defined within a structure."));
             }
             else
             {
                 throwAddressableError<SyntaxError>(FString("Invalid syntax"));
             }
         }
-        if (!braceClosed)
-        {
-            throwAddressableError<SyntaxError>(FString("braces are not closed"));
-        }
+        if (!braceClosed) { throwAddressableError<SyntaxError>(FString("braces are not closed")); }
         return makeAst<Ast::StructDefSt>(isPublic, structName, fields, makeAst<Ast::BlockStatementAst>(stmts));
     }
 
@@ -409,27 +393,18 @@ namespace Fig
                 expect(TokenType::RightArrow); // ->
                 next();                        // consume `->`
 
-                expect(TokenType::Identifier, u8"return type");
-                FString returnType = currentToken().getValue();
-                next(); // consume return type
+                Ast::Expression returnType = parseExpression(0, TokenType::LeftBrace, TokenType::Semicolon);
 
                 if (isThis(TokenType::LeftBrace))
                 {
                     Ast::BlockStatement block = __parseBlockStatement();
 
-                    methods.push_back(Ast::InterfaceMethod(
-                        funcName,
-                        paras,
-                        returnType,
-                        block));
+                    methods.push_back(Ast::InterfaceMethod(funcName, paras, returnType, block));
                     continue;
                 }
                 expectSemicolon();
 
-                methods.push_back(Ast::InterfaceMethod(
-                    funcName,
-                    paras,
-                    returnType));
+                methods.push_back(Ast::InterfaceMethod(funcName, paras, returnType));
             }
             else
             {
@@ -454,7 +429,7 @@ namespace Fig
         FString structName = currentToken().getValue();
         next();                       // consume name
         expect(TokenType::LeftBrace); // {
-        next();  // consume `{`
+        next();                       // consume `{`
 
         std::vector<Ast::ImplementMethod> methods;
 
@@ -473,10 +448,7 @@ namespace Fig
                 Ast::FunctionParameters paras = __parseFunctionParameters();
                 expect(TokenType::LeftBrace);
                 Ast::BlockStatement body = __parseBlockStatement();
-                methods.push_back(Ast::ImplementMethod(
-                    funcName,
-                    paras,
-                    body));
+                methods.push_back(Ast::ImplementMethod(funcName, paras, body));
             }
             else
             {
@@ -540,15 +512,13 @@ namespace Fig
                     hasType = true;
                 }
                 expect(TokenType::RightParen); // ）
-                next(); // consume `)`
-                expect(TokenType::LeftBrace); // {
+                next();                        // consume `)`
+                expect(TokenType::LeftBrace);  // {
                 Ast::BlockStatement catchBody = __parseBlockStatement();
 
-                if (hasType)
+                if (hasType) { catches.push_back(Ast::Catch(errVarName, errVarType, catchBody)); }
+                else
                 {
-                    catches.push_back(Ast::Catch(errVarName, errVarType, catchBody));
-                }
-                else {
                     catches.push_back(Ast::Catch(errVarName, catchBody));
                 }
             }
@@ -575,17 +545,11 @@ namespace Fig
     {
         Ast::Statement stmt;
         if (isThis(TokenType::EndOfFile)) { return makeAst<Ast::EofStmt>(); }
-        else if (isThis(TokenType::Import))
-        {
-            stmt = __parseImport();
-        }
+        else if (isThis(TokenType::Import)) { stmt = __parseImport(); }
         else if (isThis(TokenType::Public))
         {
             next(); // consume `public`
-            if (isThis(TokenType::Variable) || isThis(TokenType::Const))
-            {
-                stmt = __parseVarDef(true);
-            }
+            if (isThis(TokenType::Variable) || isThis(TokenType::Const)) { stmt = __parseVarDef(true); }
             else if (isThis(TokenType::Function) and isNext(TokenType::Identifier))
             {
                 next();
@@ -596,19 +560,14 @@ namespace Fig
                 next();
                 stmt = __parseStructDef(true);
             }
-            else if (isThis(TokenType::Interface))
-            {
-                stmt = __parseInterfaceDef(true);
-            }
+            else if (isThis(TokenType::Interface)) { stmt = __parseInterfaceDef(true); }
             else
             {
-                throwAddressableError<SyntaxError>(FString(u8"Expected `var`, `const`, `function`, `struct` or `interface` after `public`"));
+                throwAddressableError<SyntaxError>(
+                    FString(u8"Expected `var`, `const`, `function`, `struct` or `interface` after `public`"));
             }
         }
-        else if (isThis(TokenType::Variable) || isThis(TokenType::Const))
-        {
-            stmt = __parseVarDef(false);
-        }
+        else if (isThis(TokenType::Variable) || isThis(TokenType::Const)) { stmt = __parseVarDef(false); }
         else if (isThis(TokenType::Function) and isNext(TokenType::Identifier))
         {
             next();
@@ -626,50 +585,20 @@ namespace Fig
             next();
             stmt = __parseInterfaceDef(false);
         }
-        else if (isThis(TokenType::Implement))
-        {
-            stmt = __parseImplement();
-        }
-        else if (isThis(TokenType::If))
-        {
-            stmt = __parseIf();
-        }
+        else if (isThis(TokenType::Implement)) { stmt = __parseImplement(); }
+        else if (isThis(TokenType::If)) { stmt = __parseIf(); }
         else if (isThis(TokenType::Else))
         {
             throwAddressableError<SyntaxError>(FString(u8"`else` without matching `if`"));
         }
-        else if (isThis(TokenType::LeftBrace))
-        {
-            stmt = __parseBlockStatement();
-        }
-        else if (isThis(TokenType::While))
-        {
-            stmt = __parseWhile();
-        }
-        else if (isThis(TokenType::For))
-        {
-            stmt = __parseFor();
-        }
-        else if (isThis(TokenType::Return))
-        {
-            stmt = __parseReturn();
-        }
-        else if (isThis(TokenType::Break))
-        {
-            stmt = __parseBreak();
-        }
-        else if (isThis(TokenType::Continue))
-        {
-            stmt = __parseContinue();
-        }
-        else if (isThis(TokenType::Throw))
-        {
-            stmt = __parseThrow();
-        }
-        else if (isThis(TokenType::Try))
-        {
-            stmt = __parseTry();
-        }
+        else if (isThis(TokenType::LeftBrace)) { stmt = __parseBlockStatement(); }
+        else if (isThis(TokenType::While)) { stmt = __parseWhile(); }
+        else if (isThis(TokenType::For)) { stmt = __parseFor(); }
+        else if (isThis(TokenType::Return)) { stmt = __parseReturn(); }
+        else if (isThis(TokenType::Break)) { stmt = __parseBreak(); }
+        else if (isThis(TokenType::Continue)) { stmt = __parseContinue(); }
+        else if (isThis(TokenType::Throw)) { stmt = __parseThrow(); }
+        else if (isThis(TokenType::Try)) { stmt = __parseTry(); }
         else if (allowExp)
         {
             // expression statement
@@ -766,7 +695,7 @@ namespace Fig
         }
         else
         {
-            condition = parseExpression(0);
+            condition = parseExpression(0, TokenType::LeftBrace);
         }
         expect(TokenType::LeftBrace); // {
         Ast::BlockStatement body = __parseBlockStatement();
@@ -784,7 +713,8 @@ namespace Fig
             throwAddressableError<SyntaxError>(u8"BlockStatement cannot be used as for loop increment");
         }
 
-        if (isThis(TokenType::If) || isThis(TokenType::While) || isThis(TokenType::For) || isThis(TokenType::Return) || isThis(TokenType::Break) || isThis(TokenType::Continue))
+        if (isThis(TokenType::If) || isThis(TokenType::While) || isThis(TokenType::For) || isThis(TokenType::Return)
+            || isThis(TokenType::Break) || isThis(TokenType::Continue))
         {
             throwAddressableError<SyntaxError>(u8"Control flow statements cannot be used as for loop increment");
         }
@@ -799,8 +729,7 @@ namespace Fig
         // TODO: support enumeration
         next(); // consume `for`
         bool paren = isThis(TokenType::LeftParen);
-        if (paren)
-            next(); // consume `(`
+        if (paren) next(); // consume `(`
         // support 3-part for loop
         // for init; condition; increment {}
         Ast::Statement initStmt = __parseStatement(false); // auto check ``
@@ -813,8 +742,7 @@ namespace Fig
             // auto guard = disableSemicolon();
             incrementStmt = __parseIncrementStatement();
         } // after parse increment, semicolon check state restored
-        if (paren)
-            expectConsume(TokenType::RightParen);           // consume `)` if has `(`
+        if (paren) expectConsume(TokenType::RightParen);    // consume `)` if has `(`
         expect(TokenType::LeftBrace);                       // {
         Ast::BlockStatement body = __parseBlockStatement(); // auto consume `}`
         return makeAst<Ast::ForSt>(initStmt, condition, incrementStmt, body);
@@ -938,10 +866,7 @@ namespace Fig
         {
             if (mode == 0)
             {
-                if (isThis(TokenType::Identifier) && isNext(TokenType::Colon))
-                {
-                    mode = 2;
-                }
+                if (isThis(TokenType::Identifier) && isNext(TokenType::Colon)) { mode = 2; }
                 else if (isThis(TokenType::Identifier) && (isNext(TokenType::Comma) || isNext(TokenType::RightBrace)))
                 {
                     mode = 3;
@@ -985,17 +910,19 @@ namespace Fig
             }
             else if (!isThis(TokenType::RightBrace))
             {
-                throwAddressableError<SyntaxError>(FString(
-                    std::format("Expect `,` or `}}` in struct initialization expression, got {}",
-                                currentToken().toString().toBasicString())));
+                throwAddressableError<SyntaxError>(
+                    FString(std::format("Expect `,` or `}}` in struct initialization expression, got {}",
+                                        currentToken().toString().toBasicString())));
             }
         }
         expect(TokenType::RightBrace);
         next(); // consume `}`
-        return makeAst<Ast::InitExprAst>(structe, args,
-                                         (mode == 1 ? Ast::InitExprAst::InitMode::Positional :
-                                                      (mode == 2 ? Ast::InitExprAst::InitMode::Named : Ast::InitExprAst::InitMode::Shorthand)));
+        return makeAst<Ast::InitExprAst>(
+            structe,
+            args,
+            static_cast<Ast::InitExprAst::InitMode>(mode));
     }
+
     Ast::Expression Parser::__parseTupleOrParenExpr()
     {
         next();
@@ -1017,8 +944,7 @@ namespace Fig
             {
                 next(); // consume ','
 
-                if (currentToken().getType() == TokenType::RightParen)
-                    break;
+                if (currentToken().getType() == TokenType::RightParen) break;
 
                 elements.push_back(parseExpression(0));
             }
@@ -1069,10 +995,7 @@ namespace Fig
             expect(TokenType::Identifier, u8"package name");
             path.push_back(currentToken().getValue());
             next(); // consume package name
-            if (isThis(TokenType::Semicolon))
-            {
-                break;
-            }
+            if (isThis(TokenType::Semicolon)) { break; }
             else if (isThis(TokenType::Dot))
             {
                 next(); // consume `.`
@@ -1092,8 +1015,7 @@ namespace Fig
         Ast::Operator op;
 
         Token tok = currentToken();
-        if (tok == EOFTok)
-            throwAddressableError<SyntaxError>(FString(u8"Unexpected end of expression"));
+        if (tok == EOFTok) throwAddressableError<SyntaxError>(FString(u8"Unexpected end of expression"));
         if (tok.getType() == stop || tok.getType() == stop2)
         {
             if (lhs == nullptr) throwAddressableError<SyntaxError>(FString(u8"Expected expression"));
@@ -1139,6 +1061,14 @@ namespace Fig
             next();
             lhs = makeAst<Ast::UnaryExprAst>(op, parseExpression(bp, stop, stop2));
         }
+        else if (tok.getType() == TokenType::New)
+        {
+            // `new` now is an independent syntax
+            next();
+            Ast::Expression operand = parseExpression(bp, TokenType::LeftBrace);
+            expect(TokenType::LeftBrace);
+            lhs = __parseInitExpr(operand);
+        }
         else
         {
             throwAddressableError<SyntaxError>(FString(u8"Unexpected token in expression:") + tok.toString());
@@ -1148,21 +1078,31 @@ namespace Fig
         while (true)
         {
             tok = currentToken();
-            if (tok.getType() == stop || tok.getType() == stop2|| tok == EOFTok) break;
+            if (tok.getType() == stop || tok.getType() == stop2 || tok == EOFTok) break;
 
             /* Postfix */
 
+            if (tok.getType() == TokenType::LeftBrace)
+            {
+                throwAddressableError<SyntaxError>(
+                    FString(u8"Since Fig v0.4.2, please use new struct{} to avoid syntax ambiguity"));
+            }
+
             if (tok.getType() == TokenType::LeftParen)
             {
                 lhs = __parseCall(lhs);
                 continue;
             }
+            // else if (tok.getType() == TokenType::LeftBrace) { lhs = __parseInitExpr(lhs); }
+            /*
+                since Fig v0.4.2, use new struct{};
 
-            if (tok.getType() == TokenType::LeftBrace)
-            {
-                lhs = __parseInitExpr(lhs);
-                continue;
-            }
+                if a == A{}
+                is A{} struct init?
+                or A a variable, {} is the body?
+
+                fuck.
+            */
 
             // member access: a.b
             if (tok.getType() == TokenType::Dot)
@@ -1189,15 +1129,17 @@ namespace Fig
                 lhs = makeAst<Ast::IndexExprAst>(lhs, indexExpr);
                 continue;
             }
-
             // ternary
             if (tok.getType() == TokenType::Question)
             {
+                auto [lbp, rbp] = getBindingPower(Ast::Operator::TernaryCond);
+                if (bp >= lbp) break;
+
                 next(); // consume ?
-                Ast::Expression trueExpr = parseExpression(0, TokenType::Colon, stop2);
-                expect(TokenType::Colon);
-                next(); // consume :
-                Ast::Expression falseExpr = parseExpression(0, TokenType::Semicolon, stop2);
+                Ast::Expression trueExpr = parseExpression(0, TokenType::Colon);
+                expectConsume(TokenType::Colon);
+
+                Ast::Expression falseExpr = parseExpression(0);
                 lhs = makeAst<Ast::TernaryExprAst>(lhs, trueExpr, falseExpr);
                 continue;
             }
@@ -1219,10 +1161,7 @@ namespace Fig
     {
         output.clear();
         Token tok = currentToken();
-        if (tok == EOFTok)
-        {
-            return output;
-        }
+        if (tok == EOFTok) { return output; }
 
         while (!isEOF())
         {

src/Parser/parser.hpp

@@ -1,13 +1,12 @@
 #pragma once
 
-#include "Ast/astBase.hpp"
+#include <Ast/astBase.hpp>
 #include <Ast/ast.hpp>
 #include <Lexer/lexer.hpp>
 #include <Core/fig_string.hpp>
 #include <Error/error.hpp>
 
 #include <memory>
-#include <print>
 #include <source_location>
 #include <unordered_map>
 
@@ -248,7 +247,7 @@ namespace Fig
 
         [[nodiscard]] SemicolonDisabler disableSemicolon() { return SemicolonDisabler(this); }
 
-        void expectSemicolon()
+        void expectSemicolon(std::source_location loc = std::source_location::current())
         {
             // if need semicolon and stream has `;`, consume it. if not need semicolon, do nothing
 
@@ -263,18 +262,18 @@ namespace Fig
             }
 
             // normal semicolon check
-            expectConsume(TokenType::Semicolon);
+            expectConsume(TokenType::Semicolon, loc);
         }
 
-        void expectConsume(TokenType type, FString expected)
+        void expectConsume(TokenType type, FString expected, std::source_location loc = std::source_location::current())
         {
-            expect(type, expected);
+            expect(type, expected, loc);
             next();
         }
 
-        void expectConsume(TokenType type)
+        void expectConsume(TokenType type, std::source_location loc = std::source_location::current())
         {
-            expect(type);
+            expect(type, loc);
             next();
         }
 
@@ -314,6 +313,8 @@ namespace Fig
         Ast::MapExpr __parseMapExpr();   // entry: current is `{`
 
         Ast::InitExpr __parseInitExpr(Ast::Expression); // entry: current is `{`, ahead is struct type exp.
+    
+
         Ast::Expression __parseTupleOrParenExpr();      // entry: current is `(`
 
         Ast::FunctionLiteralExpr __parseFunctionLiteralExpr(); // entry: current is Token::LParen after Token::Function

src/Token/token.hpp

@@ -31,6 +31,7 @@ namespace Fig
         For,       // for
         If,        // if
         Else,      // else
+        New,       // new
         Struct,    // struct
         Interface, // interface
         Implement, // impl

src/Utils/AstPrinter.hpp

@@ -111,7 +111,7 @@ private:
         printFString(node->name, 0);
         printIndent(indent + 2);
         std::cout << "Type: ";
-        printFString(node->typeName, 0);
+        printFString(node->declaredType->toString(), 0);
         if (node->expr)
         {
             printIndent(indent + 2);