diff --git a/src/Ast/Ast.hpp b/src/Ast/Ast.hpp
index 347905a..e8f5b58 100644
--- a/src/Ast/Ast.hpp
+++ b/src/Ast/Ast.hpp
@@ -16,6 +16,8 @@
 #include <Ast/Expr/MemberExpr.hpp>
 #include <Ast/Expr/NewExpr.hpp>
 #include <Ast/Expr/PrefixExpr.hpp>
+#include <Ast/Expr/TernaryExpr.hpp>
+#include <Ast/Expr/PostfixExpr.hpp>
 
 #include <Ast/Stmt/ControlFlowStmts.hpp>
 #include <Ast/Stmt/ExprStmt.hpp>
@@ -24,6 +26,8 @@
 #include <Ast/Stmt/ImplStmt.hpp>
 #include <Ast/Stmt/InterfaceDefStmt.hpp>
 #include <Ast/Stmt/StructDefStmt.hpp>
+#include <Ast/Stmt/ForStmt.hpp>
+#include <Ast/Stmt/ImportStmt.hpp>
 #include <Ast/Stmt/VarDecl.hpp>
 #include <Ast/Stmt/WhileStmt.hpp>
 #include <Ast/TypeExpr.hpp>
\ No newline at end of file
diff --git a/src/Ast/Base.hpp b/src/Ast/Base.hpp
index 746b28a..9f98c1c 100644
--- a/src/Ast/Base.hpp
+++ b/src/Ast/Base.hpp
@@ -31,6 +31,8 @@ namespace Fig
         MemberExpr,     // obj.prop
         NewExpr, // new Point{}
         LambdaExpr,
+        TernaryExpr,    // cond ? then : else
+        PostfixExpr,     // expr++ / expr--
 
         /* Statements */
         ExprStmt,
@@ -45,12 +47,16 @@ namespace Fig
         ReturnStmt,
         BreakStmt,
         ContinueStmt,
+        ForStmt,        // for loop
+        ImportStmt,     // import
 
         /* Type Expressions */
         TypeExpr,
-        NamedTypeExpr,
-        NullableTypeExpr,
+        NamedTypeExpr,   // 废弃，用 IdentiExpr/MemberExpr/ApplyExpr 替代
+        NullableTypeExpr, // 废弃，用 NullableExpr 替代
         FnTypeExpr,
+        ApplyExpr,      // 泛型实例化: List<Int>
+        NullableExpr,   // 可空后缀: Int?
     };
 
     struct AstNode
@@ -62,15 +68,6 @@ namespace Fig
         virtual ~AstNode() {};
     };
 
-    struct TypeExpr : public AstNode
-    {
-        TypeExpr()
-        {
-            type = AstType::TypeExpr;
-        }
-        virtual ~TypeExpr() = default;
-    };
-
     struct Expr : public AstNode
     {
         // 语义分析后填充
@@ -116,4 +113,55 @@ namespace Fig
             return "<BlockStmt>";
         }
     };
+
+    // --- Type Expressions (inherit Expr — 类型即值) ---
+
+    struct TypeExpr : public Expr
+    {
+        TypeExpr() { type = AstType::TypeExpr; }
+        virtual ~TypeExpr() = default;
+    };
+
+    // ApplyExpr: 泛型实例化，List<Int> → ApplyExpr(base, [Int])
+    struct ApplyExpr final : public Expr
+    {
+        Expr           *base; // 基础类型表达式
+        DynArray<Expr *> args; // 泛型参数
+
+        ApplyExpr() { type = AstType::ApplyExpr; }
+        ApplyExpr(Expr *_base, DynArray<Expr *> _args, SourceLocation _loc) :
+            base(_base), args(std::move(_args))
+        {
+            type     = AstType::ApplyExpr;
+            location = std::move(_loc);
+        }
+        virtual String toString() const override
+        {
+            String s = base->toString() + "<";
+            for (size_t i = 0; i < args.size(); ++i)
+            {
+                if (i) s += ", ";
+                s += args[i]->toString();
+            }
+            s += ">";
+            return s;
+        }
+    };
+
+    // NullableExpr: 可空后缀 Int? → NullableExpr(Int)
+    struct NullableExpr final : public Expr
+    {
+        Expr *inner;
+
+        NullableExpr() { type = AstType::NullableExpr; }
+        NullableExpr(Expr *_inner, SourceLocation _loc) : inner(_inner)
+        {
+            type     = AstType::NullableExpr;
+            location = std::move(_loc);
+        }
+        virtual String toString() const override
+        {
+            return inner->toString() + "?";
+        }
+    };
 } // namespace Fig
diff --git a/src/Ast/Expr/LambdaExpr.hpp b/src/Ast/Expr/LambdaExpr.hpp
index f418812..4e5f553 100644
--- a/src/Ast/Expr/LambdaExpr.hpp
+++ b/src/Ast/Expr/LambdaExpr.hpp
@@ -15,7 +15,7 @@ namespace Fig
         // func (params) [-> return type] ([=> expr] / [ {stmt} ])
 
         DynArray<Param *> params;
-        TypeExpr         *returnType;
+        Expr *returnType;
         AstNode          *body; // expr/blockstmt
         bool              isExprBody;
 
@@ -28,7 +28,7 @@ namespace Fig
 
         LambdaExpr(
             DynArray<Param *> _params,
-            TypeExpr         *_returnType,
+            Expr             *_returnType,
             AstNode          *_body,
             bool              _isExprBody,
             SourceLocation    _location) :
diff --git a/src/Ast/Expr/NewExpr.hpp b/src/Ast/Expr/NewExpr.hpp
index 29b785d..b52bf1f 100644
--- a/src/Ast/Expr/NewExpr.hpp
+++ b/src/Ast/Expr/NewExpr.hpp
@@ -18,14 +18,14 @@ namespace Fig
             String name;
             Expr  *value;
         };
-        TypeExpr     *typeExpr;
+        Expr *typeExpr;
         DynArray<Arg> args;
 
         NewExpr()
         {
             type = AstType::NewExpr;
         }
-        NewExpr(TypeExpr *_te, DynArray<Arg> _args, SourceLocation _loc) :
+        NewExpr(Expr *_te, DynArray<Arg> _args, SourceLocation _loc) :
             typeExpr(_te), args(std::move(_args))
         {
             type     = AstType::NewExpr;
diff --git a/src/Ast/Expr/PostfixExpr.hpp b/src/Ast/Expr/PostfixExpr.hpp
new file mode 100644
index 0000000..6812e3e
--- /dev/null
+++ b/src/Ast/Expr/PostfixExpr.hpp
@@ -0,0 +1,35 @@
+/*!
+    @file src/Ast/Expr/PostfixExpr.hpp
+    @brief expr++ / expr--
+    @author PuqiAR (im@puqiar.top)
+    @date 2026-06-06
+*/
+
+#pragma once
+
+#include <Ast/Base.hpp>
+#include <Ast/Operator.hpp>
+
+namespace Fig
+{
+    struct PostfixExpr final : public Expr
+    {
+        UnaryOperator op;
+        Expr         *operand;
+
+        PostfixExpr() { type = AstType::PostfixExpr; }
+
+        PostfixExpr(UnaryOperator _op, Expr *_operand) :
+            op(_op), operand(_operand)
+        {
+            type     = AstType::PostfixExpr;
+            location = _operand->location;
+        }
+
+        virtual String toString() const override
+        {
+            return std::format("<PostfixExpr: {} '{}'>",
+                operand->toString(), magic_enum::enum_name(op));
+        }
+    };
+} // namespace Fig
diff --git a/src/Ast/Expr/TernaryExpr.hpp b/src/Ast/Expr/TernaryExpr.hpp
new file mode 100644
index 0000000..8a32b99
--- /dev/null
+++ b/src/Ast/Expr/TernaryExpr.hpp
@@ -0,0 +1,35 @@
+/*!
+    @file src/Ast/Expr/TernaryExpr.hpp
+    @brief cond ? then : else
+    @author PuqiAR (im@puqiar.top)
+    @date 2026-06-06
+*/
+
+#pragma once
+
+#include <Ast/Base.hpp>
+
+namespace Fig
+{
+    struct TernaryExpr final : public Expr
+    {
+        Expr *cond;
+        Expr *thenExpr;
+        Expr *elseExpr;
+
+        TernaryExpr() { type = AstType::TernaryExpr; }
+
+        TernaryExpr(Expr *_cond, Expr *_then, Expr *_else, SourceLocation _loc) :
+            cond(_cond), thenExpr(_then), elseExpr(_else)
+        {
+            type     = AstType::TernaryExpr;
+            location = std::move(_loc);
+        }
+
+        virtual String toString() const override
+        {
+            return std::format("<TernaryExpr: {} ? {} : {}>",
+                cond->toString(), thenExpr->toString(), elseExpr->toString());
+        }
+    };
+} // namespace Fig
diff --git a/src/Ast/Operator.cpp b/src/Ast/Operator.cpp
index bbc8e3a..67b8ee1 100644
--- a/src/Ast/Operator.cpp
+++ b/src/Ast/Operator.cpp
@@ -16,6 +16,8 @@ namespace Fig
             {TokenType::Minus, UnaryOperator::Negate},
             {TokenType::Not, UnaryOperator::Not},
             {TokenType::Ampersand, UnaryOperator::AddressOf},
+            {TokenType::DoublePlus, UnaryOperator::Increment},
+            {TokenType::DoubleMinus, UnaryOperator::Decrement},
         };
         return unaryOpMap;
     }
@@ -40,6 +42,8 @@ namespace Fig
 
             {TokenType::And, BinaryOperator::LogicalAnd},
             {TokenType::Or, BinaryOperator::LogicalOr},
+            {TokenType::DoubleAmpersand, BinaryOperator::LogicalAnd},
+            {TokenType::DoublePipe, BinaryOperator::LogicalOr},
 
             {TokenType::Power, BinaryOperator::Power},
 
@@ -49,6 +53,7 @@ namespace Fig
             {TokenType::AsteriskEqual, BinaryOperator::MultiplyAssign},
             {TokenType::SlashEqual, BinaryOperator::DivideAssign},
             {TokenType::PercentEqual, BinaryOperator::ModuloAssign},
+            {TokenType::Caret, BinaryOperator::BitXor},
             {TokenType::CaretEqual, BinaryOperator::BitXorAssign},
 
             {TokenType::Pipe, BinaryOperator::BitOr},
@@ -56,7 +61,7 @@ namespace Fig
             {TokenType::ShiftLeft, BinaryOperator::ShiftLeft},
             {TokenType::ShiftRight, BinaryOperator::ShiftRight},
 
-            {TokenType::Dot, BinaryOperator::MemberAccess},
+            {TokenType::As, BinaryOperator::As},
         };
         return binaryOpMap;
     }
@@ -78,6 +83,8 @@ namespace Fig
             {UnaryOperator::Negate, 20001},
             {UnaryOperator::Not, 20001},
             {UnaryOperator::AddressOf, 20001},
+            {UnaryOperator::Increment, 20001},
+            {UnaryOperator::Decrement, 20001},
         };
         return unbpm;
     }
@@ -109,6 +116,7 @@ namespace Fig
             {BinaryOperator::GreaterEqual, 2100},
 
             {BinaryOperator::Is, 2100},
+            {BinaryOperator::As, 2100},
 
             {BinaryOperator::ShiftLeft, 3000},
             {BinaryOperator::ShiftRight, 3000},
@@ -117,10 +125,9 @@ namespace Fig
             {BinaryOperator::Subtract, 4000},
             {BinaryOperator::Multiply, 4500},
             {BinaryOperator::Divide, 4500},
+            {BinaryOperator::Modulo, 4500},
 
             {BinaryOperator::Power, 5000},
-
-            {BinaryOperator::MemberAccess, 40001},
         };
         return bnbpm;
     }
@@ -153,6 +160,8 @@ namespace Fig
             case BinaryOperator::BitXorAssign:
             case BinaryOperator::Power: return GetBinaryOpLBp(op) - 1;
 
+            case BinaryOperator::As: return GetBinaryOpLBp(op) + 1;
+
             default:
                 /*
                     左结合, 左绑定力 < 右
diff --git a/src/Ast/Operator.hpp b/src/Ast/Operator.hpp
index 4f36a41..f227d42 100644
--- a/src/Ast/Operator.hpp
+++ b/src/Ast/Operator.hpp
@@ -20,6 +20,8 @@ namespace Fig
         Negate,    // 取反 -
         Not,       // 逻辑非 ! / not
         AddressOf, // 取引用 &
+        Increment, // ++
+        Decrement, // --
 
         Count // 哨兵，(int) Count 获得运算符数量（注意，enum必须从 0 开始且不中断）
     };
@@ -60,6 +62,8 @@ namespace Fig
         ShiftLeft,  // 左移
         ShiftRight, // 右移
 
+        As, // as
+
         // 成员访问
         MemberAccess, // .
 
diff --git a/src/Ast/Stmt/FnDefStmt.hpp b/src/Ast/Stmt/FnDefStmt.hpp
index d5ab75f..7736bcc 100644
--- a/src/Ast/Stmt/FnDefStmt.hpp
+++ b/src/Ast/Stmt/FnDefStmt.hpp
@@ -11,34 +11,34 @@
 namespace Fig
 {
     struct Param : public AstNode {
-        String    name;
-        TypeExpr *typeSpecifier;
-        Expr     *defaultValue;
-        Type      resolvedType;
+        String name;
+        Expr  *typeSpecifier;
+        Expr  *defaultValue;
+        Type   resolvedType;
         Param() { type = AstType::AstNode; }
         virtual ~Param() = default;
     };
 
     struct PosParam final : public Param {
-        PosParam(String _n, TypeExpr *_ts, Expr *_dv, SourceLocation _loc) {
+        PosParam(String _n, Expr *_ts, Expr *_dv, SourceLocation _loc) {
             name = std::move(_n); typeSpecifier = _ts; defaultValue = _dv; location = std::move(_loc);
         }
         virtual String toString() const override { return name; }
     };
 
     struct FnDefStmt final : public Stmt {
-        String           name;
+        String            name;
         DynArray<Param *> params;
-        TypeExpr        *returnTypeSpecifier;
-        BlockStmt       *body;
-        Type             resolvedReturnType;
-        Symbol          *resolvedSymbol = nullptr; // 连接物理符号
+        Expr             *returnTypeSpecifier;
+        BlockStmt        *body;
+        Type              resolvedReturnType;
+        Symbol           *resolvedSymbol = nullptr; // 连接物理符号
 
         int protoIndex = -1; // 在CompiledModule扁平化protos的下标
         DynArray<UpvalueInfo> upvalues;
 
         FnDefStmt() { type = AstType::FnDefStmt; }
-        FnDefStmt(bool _p, String _n, DynArray<Param *> _pa, TypeExpr *_rt, BlockStmt *_b, SourceLocation _loc)
+        FnDefStmt(bool _p, String _n, DynArray<Param *> _pa, Expr *_rt, BlockStmt *_b, SourceLocation _loc)
             : name(std::move(_n)), params(std::move(_pa)), returnTypeSpecifier(_rt), body(_b)
         {
             type = AstType::FnDefStmt; isPublic = _p; location = std::move(_loc);
diff --git a/src/Ast/Stmt/ForStmt.hpp b/src/Ast/Stmt/ForStmt.hpp
new file mode 100644
index 0000000..718d346
--- /dev/null
+++ b/src/Ast/Stmt/ForStmt.hpp
@@ -0,0 +1,32 @@
+/*!
+    @file src/Ast/Stmt/ForStmt.hpp
+    @brief for loop
+    @author PuqiAR (im@puqiar.top)
+    @date 2026-06-06
+*/
+
+#pragma once
+
+#include <Ast/Base.hpp>
+
+namespace Fig
+{
+    struct ForStmt final : public Stmt
+    {
+        Stmt      *init;
+        Expr      *cond;
+        Expr      *step;
+        BlockStmt *body;
+
+        ForStmt() { type = AstType::ForStmt; }
+
+        ForStmt(Stmt *_init, Expr *_cond, Expr *_step, BlockStmt *_body, SourceLocation _loc) :
+            init(_init), cond(_cond), step(_step), body(_body)
+        {
+            type     = AstType::ForStmt;
+            location = std::move(_loc);
+        }
+
+        virtual String toString() const override { return "<ForStmt>"; }
+    };
+} // namespace Fig
diff --git a/src/Ast/Stmt/ImplStmt.hpp b/src/Ast/Stmt/ImplStmt.hpp
index 73af617..12d9b3c 100644
--- a/src/Ast/Stmt/ImplStmt.hpp
+++ b/src/Ast/Stmt/ImplStmt.hpp
@@ -11,11 +11,11 @@ namespace Fig
 {
     struct ImplStmt final : public Stmt
     {
-        TypeExpr             *interfaceType;
-        TypeExpr             *structType;
+        Expr *interfaceType;
+        Expr *structType;
         DynArray<FnDefStmt *> methods;
 
-        ImplStmt(TypeExpr *_it, TypeExpr *_st, DynArray<FnDefStmt *> _m, SourceLocation _loc) :
+        ImplStmt(Expr *_it, Expr *_st, DynArray<FnDefStmt *> _m, SourceLocation _loc) :
             interfaceType(_it), structType(_st), methods(std::move(_m))
         {
             type     = AstType::ImplStmt;
diff --git a/src/Ast/Stmt/ImportStmt.hpp b/src/Ast/Stmt/ImportStmt.hpp
new file mode 100644
index 0000000..ec8230a
--- /dev/null
+++ b/src/Ast/Stmt/ImportStmt.hpp
@@ -0,0 +1,33 @@
+/*!
+    @file src/Ast/Stmt/ImportStmt.hpp
+    @brief import
+    @author PuqiAR (im@puqiar.top)
+    @date 2026-06-06
+*/
+
+#pragma once
+
+#include <Ast/Base.hpp>
+
+namespace Fig
+{
+    struct ImportStmt final : public Stmt
+    {
+        String path;
+        bool   isFileImport;
+
+        ImportStmt() { type = AstType::ImportStmt; }
+
+        ImportStmt(String _path, bool _isFileImport, SourceLocation _loc) :
+            path(std::move(_path)), isFileImport(_isFileImport)
+        {
+            type     = AstType::ImportStmt;
+            location = std::move(_loc);
+        }
+
+        virtual String toString() const override
+        {
+            return std::format("<ImportStmt '{}'{}>", path, isFileImport ? " [file]" : "");
+        }
+    };
+} // namespace Fig
diff --git a/src/Ast/Stmt/InterfaceDefStmt.hpp b/src/Ast/Stmt/InterfaceDefStmt.hpp
index 52d442c..f6e333f 100644
--- a/src/Ast/Stmt/InterfaceDefStmt.hpp
+++ b/src/Ast/Stmt/InterfaceDefStmt.hpp
@@ -16,8 +16,8 @@ namespace Fig
         struct Method
         {
             String              name;
-            DynArray<TypeExpr*> params;
-            TypeExpr           *retType;
+            DynArray<Expr*> params;
+            Expr *retType;
             SourceLocation      location;
         };
 
diff --git a/src/Ast/Stmt/StructDefStmt.hpp b/src/Ast/Stmt/StructDefStmt.hpp
index edf2add..56a2030 100644
--- a/src/Ast/Stmt/StructDefStmt.hpp
+++ b/src/Ast/Stmt/StructDefStmt.hpp
@@ -17,7 +17,7 @@ namespace Fig
             bool typeInfer;
 
             String    name;
-            TypeExpr *type;
+            Expr *type;
             Expr *initExpr;
         };
         bool                  isPublic;
diff --git a/src/Ast/Stmt/VarDecl.hpp b/src/Ast/Stmt/VarDecl.hpp
index 5fa31c0..78a67e4 100644
--- a/src/Ast/Stmt/VarDecl.hpp
+++ b/src/Ast/Stmt/VarDecl.hpp
@@ -15,7 +15,7 @@ namespace Fig
     struct VarDecl final : public Stmt
     {
         String name;
-        TypeExpr  *typeSpecifier;
+        Expr     *typeSpecifier;
         bool isInfer; // 是否用了 := 类型推断
         Expr  *initExpr;
 
@@ -26,7 +26,7 @@ namespace Fig
             type = AstType::VarDecl;
         }
 
-        VarDecl(bool _isPublic, String _name, TypeExpr *_typeSpecifier, bool _isInfer, Expr *_initExpr, SourceLocation _location) :
+        VarDecl(bool _isPublic, String _name, Expr *_typeSpecifier, bool _isInfer, Expr *_initExpr, SourceLocation _location) :
             name(std::move(_name)),
             typeSpecifier(_typeSpecifier),
             isInfer(_isInfer),
diff --git a/src/Ast/TypeExpr.hpp b/src/Ast/TypeExpr.hpp
index 82c68d0..9615009 100644
--- a/src/Ast/TypeExpr.hpp
+++ b/src/Ast/TypeExpr.hpp
@@ -12,13 +12,13 @@ namespace Fig
     struct NamedTypeExpr final : public TypeExpr
     {
         DynArray<String>     path;
-        DynArray<TypeExpr *> arguments;
+        DynArray<Expr *> arguments;
 
         NamedTypeExpr()
         {
             type = AstType::NamedTypeExpr;
         }
-        NamedTypeExpr(DynArray<String> _p, DynArray<TypeExpr *> _args, SourceLocation _loc) :
+        NamedTypeExpr(DynArray<String> _p, DynArray<Expr *> _args, SourceLocation _loc) :
             path(std::move(_p)), arguments(std::move(_args))
         {
             type     = AstType::NamedTypeExpr;
@@ -51,9 +51,9 @@ namespace Fig
 
     struct NullableTypeExpr final : public TypeExpr
     {
-        TypeExpr *inner;
+        Expr *inner;
 
-        NullableTypeExpr(TypeExpr *_inner, SourceLocation _loc) : inner(_inner)
+        NullableTypeExpr(Expr *_inner, SourceLocation _loc) : inner(_inner)
         {
             type     = AstType::NullableTypeExpr;
             location = std::move(_loc);
@@ -69,10 +69,10 @@ namespace Fig
     {
         // func (paratypes...) -> return_type
 
-        DynArray<TypeExpr *> paraTypes;
-        TypeExpr *returnType;
+        DynArray<Expr *> paraTypes;
+        Expr *returnType;
 
-        FnTypeExpr(DynArray<TypeExpr *> _paraTypes, TypeExpr *_returnType) :
+        FnTypeExpr(DynArray<Expr *> _paraTypes, Expr *_returnType) :
             paraTypes(std::move(_paraTypes)), returnType(_returnType)
         {
             type = AstType::FnTypeExpr;
diff --git a/src/Compiler/ExprCompiler.cpp b/src/Compiler/ExprCompiler.cpp
index ab6a1a9..9b6d701 100644
--- a/src/Compiler/ExprCompiler.cpp
+++ b/src/Compiler/ExprCompiler.cpp
@@ -1,6 +1,6 @@
 /*!
     @file src/Compiler/ExprCompiler.cpp
-    @brief 表达式编译器实现：水位线控制Register与零拷贝复用机制
+    @brief 表达式编译
 */
 
 #include <Ast/Expr/CallExpr.hpp>
@@ -167,7 +167,7 @@ namespace Fig
 
                 if (sym->location == SymbolLocation::Local)
                 {
-                    // 零拷贝直读：如果是临时求值，直接返回变量的物理槽位，禁止产生副本
+                    // no-copy for temp eval
                     if (target == NO_REG)
                         return static_cast<Register>(sym->index);
 
@@ -253,7 +253,7 @@ namespace Fig
                         &c->location);
                 }
 
-                // 回滚水位线, 释放传参时的临时占用
+                // free arg temps
                 current->freereg = mark;
 
                 // 目若 target 未指定，allocateReg 将复用 baseReg，实现零开销回写
@@ -317,7 +317,7 @@ namespace Fig
                     return r_val;
                 }
 
-                Register mark = current->freereg; // 记录水位线
+                Register mark = current->freereg; // mark
 
                 auto r_l = compileExpr(in->left);
                 if (!r_l)
diff --git a/src/Compiler/StmtCompiler.cpp b/src/Compiler/StmtCompiler.cpp
index 6e1ace7..2556545 100644
--- a/src/Compiler/StmtCompiler.cpp
+++ b/src/Compiler/StmtCompiler.cpp
@@ -1,6 +1,6 @@
 /*!
     @file src/Compiler/StmtCompiler.cpp
-    @brief 语句编译器实现：实装水位线机制，彻底消灭硬编码寄存器释放
+    @brief 语句编译
 */
 
 #include <Ast/Stmt/FnDefStmt.hpp>
@@ -35,7 +35,7 @@ namespace Fig
                 auto *v = static_cast<VarDecl *>(stmt);
                 if (current->enclosing == nullptr) // 处理全局变量
                 {
-                    Register mark   = current->freereg; // 记录水位线
+                    Register mark   = current->freereg; // mark
                     auto     regRes = compileExpr(v->initExpr);
                     if (!regRes)
                         return std::unexpected(regRes.error());
@@ -74,7 +74,7 @@ namespace Fig
                     Proto *newProto        = new Proto();
                     newProto->name         = f->name;
                     newProto->numParams    = static_cast<uint8_t>(f->params.size());
-                    newProto->maxRegisters = newProto->numParams; // 同步水位线
+                    newProto->maxRegisters = newProto->numParams; // sync
 
                     f->protoIndex = static_cast<int>(module->protos.size());
                     module->protos.push_back(newProto);
@@ -141,7 +141,7 @@ namespace Fig
                 auto         *i = static_cast<IfStmt *>(stmt);
                 DynArray<int> exitJumps;
 
-                Register mark   = current->freereg; // 记录水位线
+                Register mark   = current->freereg; // mark
                 auto     r_cond = compileExpr(i->cond);
                 if (!r_cond)
                     return std::unexpected(r_cond.error());
@@ -204,7 +204,7 @@ namespace Fig
                 auto *w        = static_cast<WhileStmt *>(stmt);
                 int   startIdx = static_cast<int>(current->proto->code.size());
 
-                Register mark   = current->freereg; // 记录水位线
+                Register mark   = current->freereg; // mark
                 auto     r_cond = compileExpr(w->cond);
                 if (!r_cond)
                     return std::unexpected(r_cond.error());
@@ -228,7 +228,7 @@ namespace Fig
 
             case AstType::ReturnStmt: {
                 auto    *rs   = static_cast<ReturnStmt *>(stmt);
-                Register mark = current->freereg; // 记录水位线
+                Register mark = current->freereg; // mark
                 Register retReg;
 
                 if (rs->value)
@@ -253,7 +253,7 @@ namespace Fig
             }
 
             case AstType::ExprStmt: {
-                Register mark = current->freereg; // 记录水位线
+                Register mark = current->freereg; // mark
                 auto     reg  = compileExpr(static_cast<ExprStmt *>(stmt)->expr);
                 if (!reg)
                     return std::unexpected(reg.error());
diff --git a/src/Parser/ExprParser.cpp b/src/Parser/ExprParser.cpp
index d9f4f6f..6bad03b 100644
--- a/src/Parser/ExprParser.cpp
+++ b/src/Parser/ExprParser.cpp
@@ -161,7 +161,7 @@ namespace Fig
         {
             return std::unexpected(type_result.error());
         }
-        TypeExpr *type = *type_result;
+        Expr *type = *type_result;
 
         if (!match(TokenType::LeftBrace))
         {
@@ -175,6 +175,8 @@ namespace Fig
                 new Point{1, 2}
             Named:
                 new Point{x = 1, y = 2}
+            Shorthand:
+                new Point{y, x}
         */
 
         DynArray<NewExpr::Arg> args;
@@ -195,11 +197,12 @@ namespace Fig
                 break;
             }
 
-            if (currentToken().isIdentifier() && peekToken().type == TokenType::Assign)
+            // named arg
+            if (currentToken().isIdentifier() && peekToken().type == TokenType::Colon)
             {
                 const Token &name_token = consumeToken();
                 const String &name = srcManager.GetSub(name_token.index, name_token.length);
-                consumeToken(); // consume `=`
+                consumeToken(); // consume `:`
 
                 SET_STOP_AT(TokenType::Comma, TokenType::RightBrace); // , / }
                 auto result = parseExpression();
@@ -213,7 +216,20 @@ namespace Fig
                     *result
                 });
             }
-            else 
+            // shorthand
+            else if (currentToken().isIdentifier()
+                     && (peekToken().type == TokenType::Comma || peekToken().type == TokenType::RightBrace))
+            {
+                const Token &name_token = consumeToken();
+                const String &name = srcManager.GetSub(name_token.index, name_token.length);
+
+                
+                
+                IdentiExpr *ident =
+                    arena.Allocate<IdentiExpr>(name, makeSourceLocation(name_token));
+                args.push_back(NewExpr::Arg{name, ident});
+            }
+            else
             {
                 SET_STOP_AT(TokenType::Comma, TokenType::RightBrace); // , / }
                 auto result = parseExpression();
@@ -226,7 +242,7 @@ namespace Fig
                     .value = *result
                 });
             }
-            
+
 
             if (match(TokenType::Comma))
             {
@@ -273,7 +289,7 @@ namespace Fig
         }
         params = *paraResult;
 
-        TypeExpr *returnType = nullptr;
+        Expr *returnType = nullptr;
         Token     rightArrowToken;
         if (match(TokenType::RightArrow)) // ->
         {
@@ -332,6 +348,7 @@ namespace Fig
         Expr *lhs   = nullptr;
         Token token = currentToken();
 
+        // NUD
         if (token.isIdentifier())
         {
             const auto &lhs_result = parseIdentiExpr();
@@ -350,7 +367,7 @@ namespace Fig
             }
             lhs = *lhs_result;
         }
-        else if (IsTokenOp(token.type, false)) // 是否是一元运算符
+        else if (IsTokenOp(token.type, false)) // 是否是一元前缀运算符
         {
             const auto &lhs_result = parsePrefixExpr();
             if (!lhs_result)
@@ -408,6 +425,7 @@ namespace Fig
                 makeSourceLocation(prevToken())));
         }
 
+        // LED
         while (true)
         {
             token = currentToken();
@@ -416,57 +434,116 @@ namespace Fig
                 break;
             }
 
-            if (IsTokenOp(token.type /* isBinary = true */)) // 是否为二元运算符
+            // is / as
+            if (token.type == TokenType::Is || token.type == TokenType::As)
+            {
+                BinaryOperator op  = TokenToBinaryOp(token);
+                BindingPower   lbp = GetBinaryOpLBp(op);
+                if (rbp >= lbp)
+                {
+                    break;
+                }
+                consumeToken(); // consume `is` or `as`
+                auto typeRes = parseTypeExpr();
+                if (!typeRes)
+                {
+                    return std::unexpected(typeRes.error());
+                }
+                lhs = arena.Allocate<InfixExpr>(lhs, op, *typeRes);
+            }
+            // binary
+            else if (IsTokenOp(token.type /* isBinary = true */))
             {
                 BinaryOperator op  = TokenToBinaryOp(token);
                 BindingPower   lbp = GetBinaryOpLBp(op);
                 if (rbp >= lbp)
                 {
-                    // 前操作数的右绑定力比当前操作数的左绑定力大
-                    // lhs被吸走
                     break;
                 }
 
                 auto result = parseInfixExpr(lhs);
                 if (!result)
                 {
-                    resetTermintors();
                     return result;
                 }
                 lhs = *result;
             }
-            // 后缀运算符优先级非常大，几乎永远跟在操作数后面，因此我们可以直接结合
-            // 而不用走正常路径
-            else if (token.type == TokenType::LeftBracket) // `[`
+            // [index]
+            else if (token.type == TokenType::LeftBracket)
             {
                 const auto &expr_result = parseIndexExpr(lhs);
                 if (!expr_result)
                 {
-                    resetTermintors();
                     return expr_result;
                 }
                 lhs = *expr_result;
             }
-            else if (token.type == TokenType::LeftParen) // `(`
+            // call
+            else if (token.type == TokenType::LeftParen)
             {
                 const auto &expr_result = parseCallExpr(lhs);
                 if (!expr_result)
                 {
-                    resetTermintors();
                     return expr_result;
                 }
                 lhs = *expr_result;
             }
+            // .member
+            else if (token.type == TokenType::Dot)
+            {
+                consumeToken(); // consume `.`
+                if (!currentToken().isIdentifier())
+                {
+                    return std::unexpected(
+                        makeUnexpectTokenError("MemberExpr", "identifier after `.`", currentToken()));
+                }
+                const Token  &nameToken = consumeToken();
+                const String &name =
+                    srcManager.GetSub(nameToken.index, nameToken.length);
+                SourceLocation loc = makeSourceLocation(nameToken);
+                lhs = arena.Allocate<MemberExpr>(lhs, name, loc);
+            }
+            // x++ x--
+            else if (token.type == TokenType::DoublePlus || token.type == TokenType::DoubleMinus)
+            {
+                UnaryOperator op = TokenToUnaryOp(consumeToken());
+                lhs = arena.Allocate<PostfixExpr>(op, lhs);
+            }
+            // ?:
+            else if (token.type == TokenType::Question)
+            {
+                // ?: 最低优先
+                // 赋值 rbp = 101，所以只有当 rbp < 100 时才可能进到三元
+                // 实际上三元是最低优先级的非赋值运算符，我们给一个很小的 lbp
+                constexpr BindingPower TERNARY_LBP = 150;
+                if (rbp >= TERNARY_LBP)
+                {
+                    break;
+                }
+                consumeToken(); // consume `?`
+                auto thenRes = parseExpression(0); // 重置绑定力，右结合
+                if (!thenRes)
+                {
+                    return std::unexpected(thenRes.error());
+                }
+                if (!match(TokenType::Colon))
+                {
+                    return std::unexpected(
+                        makeUnexpectTokenError("TernaryExpr", "`:` for else branch", currentToken()));
+                }
+                auto elseRes = parseExpression(TERNARY_LBP - 1); // 右结合
+                if (!elseRes)
+                {
+                    return std::unexpected(elseRes.error());
+                }
+                lhs = arena.Allocate<TernaryExpr>(lhs, *thenRes, *elseRes, lhs->location);
+            }
             else
             {
-                // return std::unexpected(Error(ErrorType::ExpectedExpression,
-                //     "expression unexpectedly ended",
-                //     "insert expressions",
-                //     makeSourceLocation(token)));
                 return lhs;
             }
         }
         return lhs;
     }
 
-}; // namespace Fig
\ No newline at end of file
+}; // namespace Fig
diff --git a/src/Parser/Parser.cpp b/src/Parser/Parser.cpp
index 5ab24ff..f30c730 100644
--- a/src/Parser/Parser.cpp
+++ b/src/Parser/Parser.cpp
@@ -15,12 +15,16 @@ namespace Fig
         
         while (currentToken().type != TokenType::EndOfFile)
         {
+            if (lexerError)
+            {
+                return std::unexpected(*lexerError);
+            }
             auto result = parseStatement();
             if (!result)
             {
                 return std::unexpected(result.error());
             }
-            
+
             Stmt *stmt = *result;
             if (stmt)
             {
diff --git a/src/Parser/Parser.hpp b/src/Parser/Parser.hpp
index e80ec37..fabc521 100644
--- a/src/Parser/Parser.hpp
+++ b/src/Parser/Parser.hpp
@@ -35,6 +35,7 @@ namespace Fig
         bool   isEOF = false;
 
         Diagnostics &diagnostics;
+        std::optional<Error> lexerError;  // 词法错误缓存，避免 exit/abort
 
         // 惰性获取下一个 Token，跳过注释
         Token nextToken()
@@ -49,8 +50,12 @@ namespace Fig
                 auto result = lexer.NextToken();
                 if (!result)
                 {
-                    ReportError(result.error(), srcManager);
-                    std::exit(-1);
+                    lexerError = result.error();
+                    isEOF      = true;
+                    Token eof  = {0, 0, TokenType::EndOfFile};
+                    buffer.push_back(eof);
+                    index = buffer.size() - 1;
+                    return buffer[index];
                 }
                 const Token &token = result.value();
                 if (token.type == TokenType::Comments)
@@ -84,8 +89,12 @@ namespace Fig
                 auto result = lexer.NextToken();
                 if (!result)
                 {
-                    ReportError(result.error(), srcManager);
-                    std::abort();
+                    lexerError = result.error();
+                    isEOF      = true;
+                    Token eof  = {0, 0, TokenType::EndOfFile};
+                    buffer.push_back(eof);
+                    index = buffer.size() - 1;
+                    return buffer.back();
                 }
                 if (result->type == TokenType::Comments)
                     continue;
@@ -158,20 +167,10 @@ namespace Fig
             return baseTerminators;
         }
 
-        std::unordered_set<TokenType> &getTerminators()
-        {
-            static std::unordered_set<TokenType> terminators(getBaseTerminators());
-            return terminators;
-        }
-        void resetTermintors()
-        {
-            getTerminators() = getBaseTerminators();
-        }
-
         bool shouldTerminate()
         {
             const Token &token = currentToken();
-            if (getTerminators().contains(token.type))
+            if (getBaseTerminators().contains(token.type))
                 return true;
             for (auto it = stateStack.rbegin(); it < stateStack.rend(); ++it)
             {
@@ -261,9 +260,9 @@ namespace Fig
 
         Result<decltype(StructDefStmt::typeParameters), Error> parseTypeParameters();
         
-        Result<TypeExpr *, Error> parseTypeExpr();
-        Result<TypeExpr *, Error> parseNamedTypeExpr();
-        Result<TypeExpr *, Error> parseFnTypeExpr();
+        Result<Expr *, Error> parseTypeExpr();
+        Result<Expr *, Error> parseNamedTypeExpr();
+        Result<Expr *, Error> parseFnTypeExpr();
 
         Result<Expr *, Error> parseExpression(BindingPower = 0);
         Result<Expr *, Error> parseLiteralExpr();
@@ -277,6 +276,7 @@ namespace Fig
 
         Result<BlockStmt *, Error>       parseBlockStmt();
         Result<VarDecl *, Error>         parseVarDecl(bool);
+        Result<VarDecl *, Error>         parseConstDecl(bool);
         Result<IfStmt *, Error>          parseIfStmt();
         Result<WhileStmt *, Error>       parseWhileStmt();
         Result<DynArray<Param *>, Error> parseFnParams();
@@ -286,6 +286,8 @@ namespace Fig
         Result<Stmt *, Error> parseStructDef(bool);
         Result<Stmt *, Error> parseInterfaceDef(bool);
         Result<Stmt *, Error> parseImpl();
+        Result<Stmt *, Error> parseForStmt();
+        Result<Stmt *, Error> parseImportStmt();
 
         Result<Stmt *, Error> parseStatement();
 
diff --git a/src/Parser/ParserTest.cpp b/src/Parser/ParserTest.cpp
index 2c3da36..de096d0 100644
--- a/src/Parser/ParserTest.cpp
+++ b/src/Parser/ParserTest.cpp
@@ -5,24 +5,25 @@ int main()
 {
     using namespace Fig;
 
-    String        fileName = "test.fig";
-    String        filePath = "T:/Files/Maker/Code/MyCodingLanguage/The Fig Project/Fig/test.fig";
+    String fileName = "test.fig";
+    String filePath =
+        "T:/Files/Maker/Code/MyCodingLanguage/The Fig Project/Fig/" + fileName;
 
     SourceManager srcManager(filePath);
 
     String source = srcManager.Read();
     if (!srcManager.read)
     {
-        std::cerr << "Couldn't read file";
+        std::cerr << "Couldn't read file: " << filePath << '\n';
         return 1;
     }
 
-    Lexer  lexer(source, fileName);
+    Lexer lexer(source, fileName);
 
     Diagnostics diagnostics;
     Parser parser(lexer, srcManager, fileName, diagnostics);
 
-    auto   result = parser.Parse();
+    auto result = parser.Parse();
     if (!result)
     {
         ReportError(result.error(), srcManager);
@@ -32,8 +33,11 @@ int main()
     diagnostics.EmitAll(srcManager);
 
     Program *program = *result;
-    for (Stmt *stmt : program->nodes)
+    std::cout << "Parsed " << program->nodes.size() << " statements\n";
+    for (size_t i = 0; i < program->nodes.size(); ++i)
     {
-        std::cout << stmt->toString() << '\n';
+        std::cout << '[' << i << "] " << program->nodes[i]->toString() << '\n';
     }
-}
\ No newline at end of file
+
+    return 0;
+}
diff --git a/src/Parser/StmtParser.cpp b/src/Parser/StmtParser.cpp
index a26aed2..a774126 100644
--- a/src/Parser/StmtParser.cpp
+++ b/src/Parser/StmtParser.cpp
@@ -50,7 +50,7 @@ namespace Fig
         const String &name = srcManager.GetSub(currentToken().index, currentToken().length);
         consumeToken();
 
-        TypeExpr *typeSpeicifer = nullptr;
+        Expr *typeSpeicifer = nullptr;
         if (match(TokenType::Colon))
         {
             auto result = parseTypeExpr();
@@ -99,6 +99,79 @@ namespace Fig
         return varDecl;
     }
 
+    Result<VarDecl *, Error> Parser::parseConstDecl(bool isPublic)
+    {
+        // must init
+        StateProtector p(this, {State::ParsingVarDecl});
+
+        SourceLocation location = makeSourceLocation(consumeToken()); // consume `const`
+
+        if (currentToken().type != TokenType::Identifier)
+        {
+            return std::unexpected(makeUnexpectTokenError("ConstDecl", "const name", currentToken()));
+        }
+        const String &name = srcManager.GetSub(currentToken().index, currentToken().length);
+        consumeToken();
+
+        Expr *typeSpecifier = nullptr;
+        if (match(TokenType::Colon))
+        {
+            auto result = parseTypeExpr();
+            if (!result)
+            {
+                return std::unexpected(result.error());
+            }
+            typeSpecifier = *result;
+        }
+
+        Expr *initExpr = nullptr;
+        bool  isInfer  = false;
+        if (match(TokenType::Assign))
+        {
+            auto result = parseExpression();
+            if (!result)
+            {
+                return std::unexpected(result.error());
+            }
+            initExpr = *result;
+        }
+        else if (match(TokenType::Walrus))
+        {
+            if (typeSpecifier)
+            {
+                return std::unexpected(Error(
+                    ErrorType::SyntaxError,
+                    "used type infer but specifying the type",
+                    "change `:=` to '='",
+                    makeSourceLocation(prevToken())));
+            }
+            auto result = parseExpression();
+            if (!result)
+            {
+                return std::unexpected(result.error());
+            }
+            initExpr = *result;
+            isInfer  = true;
+        }
+        else
+        {
+            return std::unexpected(Error(
+                ErrorType::SyntaxError,
+                "const must be initialized",
+                "add '=' and an initializer expression",
+                makeSourceLocation(prevToken())));
+        }
+
+        if (!match(TokenType::Semicolon))
+        {
+            return std::unexpected(makeExpectSemicolonError());
+        }
+
+        VarDecl *varDecl =
+            arena.Allocate<VarDecl>(isPublic, name, typeSpecifier, isInfer, initExpr, location);
+        return varDecl;
+    }
+
     Result<IfStmt *, Error> Parser::parseIfStmt()
     {
         StateProtector p(this, {State::ParsingIf});
@@ -294,6 +367,123 @@ namespace Fig
         return whileStmt;
     }
 
+    Result<Stmt *, Error> Parser::parseForStmt()
+    {
+        SourceLocation location = makeSourceLocation(consumeToken()); // consume `for`
+
+        // 括号可选
+        bool hasParen = match(TokenType::LeftParen);
+
+        // init: var decl 或 表达式语句（或空）
+        Stmt *init = nullptr;
+        if (currentToken().type == TokenType::Variable)
+        {
+            auto result = parseVarDecl(false);
+            if (!result)
+                return std::unexpected(result.error());
+            init = *result;
+        }
+        else if (currentToken().type == TokenType::Semicolon)
+        {
+            // 空 init，跳过
+        }
+        else if (!isEOF)
+        {
+            // 表达式作为 init
+            auto result = parseExpression();
+            if (!result)
+                return std::unexpected(result.error());
+            init = arena.Allocate<ExprStmt>(*result);
+            if (!match(TokenType::Semicolon))
+                return std::unexpected(makeExpectSemicolonError());
+        }
+
+        // 要求分号分隔
+        if (!init && currentToken().type != TokenType::Semicolon)
+        {
+            // 如果不是 var decl 且下一个不是分号，尝试作为表达式解析并消耗分号
+            // 实际上 init 为 nullptr 的情况就是空 init，此时应该已经有分号了
+        }
+        if (init)
+        {
+            
+        }
+        else
+        {
+            if (!match(TokenType::Semicolon))
+            {
+                return std::unexpected(makeExpectSemicolonError());
+            }
+        }
+
+        // cond: 表达式（或空）
+        Expr *cond = nullptr;
+        SET_STOP_AT(TokenType::Semicolon);
+        if (currentToken().type != TokenType::Semicolon)
+        {
+            auto result = parseExpression();
+            if (!result)
+                return std::unexpected(result.error());
+            cond = *result;
+        }
+        // 确保下一个是分号
+        if (currentToken().type == TokenType::Semicolon)
+        {
+            // continue
+        }
+        if (!match(TokenType::Semicolon))
+        {
+            return std::unexpected(makeExpectSemicolonError());
+        }
+
+        // step: 表达式（或空）
+        Expr *step = nullptr;
+        if (hasParen)
+        {
+            SET_STOP_AT(TokenType::RightParen);
+        }
+        else
+        {
+            SET_STOP_AT(TokenType::LeftBrace);
+        }
+        if (hasParen && currentToken().type == TokenType::RightParen)
+        {
+            // 空 step
+        }
+        else if (!hasParen && currentToken().type == TokenType::LeftBrace)
+        {
+            // 空 step，直接进入 body
+        }
+        else if (!isEOF)
+        {
+            auto result = parseExpression();
+            if (!result)
+                return std::unexpected(result.error());
+            step = *result;
+        }
+
+        if (hasParen && !match(TokenType::RightParen))
+        {
+            return std::unexpected(
+                makeUnexpectTokenError("for stmt", "`)` to close", currentToken()));
+        }
+
+        if (currentToken().type != TokenType::LeftBrace)
+        {
+            return std::unexpected(
+                makeUnexpectTokenError("for stmt", "left brace `{`", currentToken()));
+        }
+
+        auto bodyRes = parseBlockStmt();
+        if (!bodyRes)
+        {
+            return std::unexpected(bodyRes.error());
+        }
+
+        ForStmt *forStmt = arena.Allocate<ForStmt>(init, cond, step, *bodyRes, location);
+        return forStmt;
+    }
+
     Result<DynArray<Param *>, Error> Parser::parseFnParams()
     {
         const Token      &lpToken = consumeToken();
@@ -318,7 +508,7 @@ namespace Fig
             SourceLocation location = makeSourceLocation(nToken);
             const String  &name     = srcManager.GetSub(nToken.index, nToken.length);
 
-            TypeExpr *type = nullptr;
+            Expr *type = nullptr;
             if (match(TokenType::Colon))
             {
                 auto result = parseTypeExpr();
@@ -345,8 +535,32 @@ namespace Fig
             PosParam *posParam = arena.Allocate<PosParam>(name, type, defaultValue, location);
             params.push_back(posParam);
 
+            // 可变参数: ... (跟在最后一个参数后面)
+            if (match(TokenType::TripleDot))
+            {
+                // 标记最后一个参数为可变参数
+                // 通过 VarParam 标记
+                // 当前用 VarParam 包装最后一个 param
+                // 简单方案：创建一个带 variadic 标记的 param
+                // TODO: 改用专门的 VarParam AST 节点
+                // 暂时用 flag 标记在 posParam 上
+
+                if (!match(TokenType::RightParen))
+                {
+                    return std::unexpected(
+                        makeUnexpectTokenError("fn params", "`)` after `...`", currentToken()));
+                }
+                // 直接返回，可变参数后面不能再有参数
+                break;
+            }
+
             if (match(TokenType::Comma))
             {
+                if (match(TokenType::RightParen))
+                {
+                    // 尾部逗号允许，如 func(a, b,)
+                    break;
+                }
                 if (!currentToken().isIdentifier())
                 {
                     return std::unexpected(
@@ -385,7 +599,7 @@ namespace Fig
         }
         params = *paraResult;
 
-        TypeExpr *returnType = nullptr;
+        Expr *returnType = nullptr;
         if (match(TokenType::RightArrow))
         {
             auto result = parseTypeExpr();
@@ -405,11 +619,6 @@ namespace Fig
                 return std::unexpected(result.error());
             }
 
-            // if (!match(TokenType::Semicolon)) // ;
-            // {
-            //     return std::unexpected(makeExpectSemicolonError(prevToken()));
-            // }
-
             if (match(TokenType::Semicolon))
             {
                 diagnostics.Report(Error(
@@ -518,7 +727,7 @@ namespace Fig
 
             // (public) field_name (: Type) (= expr) / (:= expr)
 
-            bool isPublic = match(TokenType::Public);
+            bool isPublicField = match(TokenType::Public);
             if (currentToken().isIdentifier())
             {
                 const Token  &name_tok   = consumeToken();
@@ -533,11 +742,11 @@ namespace Fig
                     }
 
                     stDef->fields.push_back(
-                        StructDefStmt::Field{isPublic, true, field_name, nullptr, *result});
+                        StructDefStmt::Field{isPublicField, true, field_name, nullptr, *result});
                 }
                 else
                 {
-                    TypeExpr *type     = nullptr;
+                    Expr *type     = nullptr;
                     Expr     *initExpr = nullptr;
 
                     if (match(TokenType::Colon)) // :
@@ -560,7 +769,7 @@ namespace Fig
                         initExpr = *result;
                     }
                     stDef->fields.push_back(
-                        StructDefStmt::Field{isPublic, false, field_name, type, initExpr});
+                        StructDefStmt::Field{isPublicField, false, field_name, type, initExpr});
                 }
                 if (!match(TokenType::Semicolon))
                 {
@@ -569,7 +778,7 @@ namespace Fig
             }
             else if (currentToken().type == TokenType::Function)
             {
-                auto result = parseFnDefStmt(isPublic);
+                auto result = parseFnDefStmt(isPublicField);
                 if (!result)
                 {
                     return result;
@@ -587,113 +796,444 @@ namespace Fig
         return stDef;
     }
 
-    Result<Stmt *, Error> Parser::parseStatement()
+    Result<Stmt *, Error> Parser::parseInterfaceDef(bool isPublic)
     {
-        StateProtector p(this, {State::Standby});
+        SourceLocation location = makeSourceLocation(consumeToken()); // consume `interface`
 
-        if (currentToken().type == TokenType::Public)
+        if (!currentToken().isIdentifier())
         {
-            consumeToken();
-            if (currentToken().type == TokenType::Variable)
-            {
-                return parseVarDecl(true);
-            }
-
-            if (currentToken().type == TokenType::Function)
-            {
-                return parseFnDefStmt(true);
-            }
-
-            if (currentToken().type == TokenType::Struct)
-            {
-                return parseStructDef(true);
-            }
-
             return std::unexpected(
-                makeUnexpectTokenError("public", "var/const/func/struct", currentToken()));
+                makeUnexpectTokenError("InterfaceDef", "interface name", currentToken()));
         }
 
-        if (currentToken().type == TokenType::LeftBrace)
+        const Token  &nameToken = consumeToken();
+        const String &name      = srcManager.GetSub(nameToken.index, nameToken.length);
+
+        if (!match(TokenType::LeftBrace))
         {
-            return parseBlockStmt();
+            return std::unexpected(
+                makeUnexpectTokenError("InterfaceDef", "lbrace '{'", currentToken()));
         }
 
-        if (currentToken().type == TokenType::Variable)
-        {
-            return parseVarDecl(false);
-        }
+        const Token &lbToken = prevToken();
 
-        if (currentToken().type == TokenType::If)
-        {
-            return parseIfStmt();
-        }
+        InterfaceDefStmt *ifaceDef = arena.Allocate<InterfaceDefStmt>();
+        ifaceDef->isPublic = isPublic;
+        ifaceDef->name     = name;
+        ifaceDef->location = location;
 
-        if (currentToken().type == TokenType::While)
+        while (true)
         {
-            return parseWhileStmt();
-        }
+            if (isEOF)
+            {
+                return std::unexpected(Error(
+                    ErrorType::SyntaxError,
+                    "unclosed braces in interface def",
+                    "insert '}'",
+                    makeSourceLocation(lbToken)));
+            }
+            if (match(TokenType::RightBrace))
+            {
+                break;
+            }
 
-        if (currentToken().type == TokenType::Function && peekToken().isIdentifier())
-        {
-            return parseFnDefStmt(false);
-        }
+            // interface 方法需要 `func` 关键字
+            if (currentToken().type != TokenType::Function)
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("InterfaceDef", "`func` for method", currentToken()));
+            }
+            consumeToken(); // consume `func`
 
-        if (currentToken().type == TokenType::Struct)
-        {
-            return parseStructDef(false);
-        }
+            if (!currentToken().isIdentifier())
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("InterfaceDef", "method name", currentToken()));
+            }
 
-        if (currentToken().type == TokenType::Return)
-        {
-            return parseReturnStmt();
-        }
+            const Token  &methodNameToken = consumeToken();
+            const String &methodName =
+                srcManager.GetSub(methodNameToken.index, methodNameToken.length);
 
-        if (match(TokenType::Break))
-        {
-            SourceLocation location = makeSourceLocation(prevToken());
-            if (!match(TokenType::Semicolon))
+            // 参数列表
+            if (!match(TokenType::LeftParen))
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("InterfaceDef", "`(` for method params", currentToken()));
+            }
+
+            // 解析参数类型（接口方法只声明类型，无参数名）
+            DynArray<InterfaceDefStmt::Method> methods; // placeholder
+            DynArray<Expr *> paramTypes;
+
+            while (true)
+            {
+                if (isEOF)
+                {
+                    return std::unexpected(Error(
+                        ErrorType::SyntaxError,
+                        "unclosed parenthese in interface method",
+                        "insert ')'",
+                        makeSourceLocation(methodNameToken)));
+                }
+                if (match(TokenType::RightParen))
+                {
+                    break;
+                }
+
+                // 参数: name : Type
+                if (!currentToken().isIdentifier())
+                {
+                    return std::unexpected(
+                        makeUnexpectTokenError("InterfaceDef", "param name", currentToken()));
+                }
+                consumeToken(); // consume param name (unused in interface)
+
+                Expr *paramType = nullptr;
+                if (match(TokenType::Colon))
+                {
+                    auto res = parseTypeExpr();
+                    if (!res)
+                        return std::unexpected(res.error());
+                    paramType = *res;
+                }
+                // 接口方法参数类型可选（如果没有标注则默认 Any）
+                paramTypes.push_back(paramType);
+
+                if (match(TokenType::Comma))
+                {
+                    if (match(TokenType::RightParen))
+                        break; // 尾部逗号
+                }
+            }
+
+            // 返回类型（接口方法必须有返回类型）
+            Expr *returnType = nullptr;
+            if (match(TokenType::RightArrow))
+            {
+                auto res = parseTypeExpr();
+                if (!res)
+                    return std::unexpected(res.error());
+                returnType = *res;
+            }
+            else
+            {
+                return std::unexpected(Error(
+                    ErrorType::SyntaxError,
+                    "interface method must specify return type with `->`",
+                    "add `-> ReturnType`",
+                    makeSourceLocation(methodNameToken)));
+            }
+
+            // 默认实现？（方法签名后直接跟 `{` 表示默认实现）
+            BlockStmt *defaultBody = nullptr;
+            if (currentToken().type == TokenType::LeftBrace)
+            {
+                auto bodyRes = parseBlockStmt();
+                if (!bodyRes)
+                    return std::unexpected(bodyRes.error());
+                defaultBody = *bodyRes;
+            }
+            else if (!match(TokenType::Semicolon))
             {
                 return std::unexpected(makeExpectSemicolonError());
             }
-            BreakStmt *breakStmt = arena.Allocate<BreakStmt>(location);
-            return breakStmt;
+
+            // 构建方法签名
+            InterfaceDefStmt::Method method;
+            method.name     = methodName;
+            method.params   = paramTypes;
+            method.retType  = returnType;
+            method.location = makeSourceLocation(methodNameToken);
+            ifaceDef->methods.push_back(std::move(method));
+
+            // TODO: 存储默认实现体的 AST
+            // 当前 InterfaceDefStmt::Method 没有 body 字段
+            // 如果需要默认实现，需要扩展 AST
+            (void) defaultBody;
         }
 
-        if (match(TokenType::Continue))
+        return ifaceDef;
+    }
+
+    Result<Stmt *, Error> Parser::parseImpl()
+    {
+        SourceLocation location = makeSourceLocation(consumeToken()); // consume `impl`
+
+        // impl InterfaceName for StructName { methods... }
+        auto interfaceTypeRes = parseTypeExpr();
+        if (!interfaceTypeRes)
+            return std::unexpected(interfaceTypeRes.error());
+        Expr *interfaceType = *interfaceTypeRes;
+
+        if (!match(TokenType::For))
         {
-            SourceLocation location = makeSourceLocation(prevToken());
-            if (!match(TokenType::Semicolon))
+            return std::unexpected(
+                makeUnexpectTokenError("ImplStmt", "`for` keyword", currentToken()));
+        }
+
+        auto structTypeRes = parseTypeExpr();
+        if (!structTypeRes)
+            return std::unexpected(structTypeRes.error());
+        Expr *structType = *structTypeRes;
+
+        if (!match(TokenType::LeftBrace))
+        {
+            return std::unexpected(
+                makeUnexpectTokenError("ImplStmt", "lbrace `{`", currentToken()));
+        }
+
+        const Token &lbToken = prevToken();
+
+        DynArray<FnDefStmt *> methods;
+
+        while (true)
+        {
+            if (isEOF)
             {
-                return std::unexpected(makeExpectSemicolonError());
+                return std::unexpected(Error(
+                    ErrorType::SyntaxError,
+                    "unclosed braces in impl block",
+                    "insert '}'",
+                    makeSourceLocation(lbToken)));
             }
-            ContinueStmt *continueStmt = arena.Allocate<ContinueStmt>(location);
-            return continueStmt;
+            if (match(TokenType::RightBrace))
+            {
+                break;
+            }
+
+            // impl 方法需要 `func` 关键字
+            if (currentToken().type != TokenType::Function)
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("ImplStmt", "`func` for method", currentToken()));
+            }
+            consumeToken(); // consume `func`
+
+            if (!currentToken().isIdentifier())
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("ImplStmt", "method name", currentToken()));
+            }
+
+            const Token  &methodNameToken = consumeToken();
+            const String &methodName =
+                srcManager.GetSub(methodNameToken.index, methodNameToken.length);
+
+            // 参数列表
+            if (!match(TokenType::LeftParen))
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("ImplStmt", "`(` for method params", currentToken()));
+            }
+
+            // 复用 FnDefStmt 来解析 impl 方法
+            // 但我们不使用 parseFnDefStmt，因为 impl 方法:
+            // 1. 不写返回类型（由 interface 约束）
+            // 2. 必须有函数体（{ }）
+
+            DynArray<Param *> fnParams;
+
+            while (true)
+            {
+                if (isEOF)
+                {
+                    return std::unexpected(Error(
+                        ErrorType::SyntaxError,
+                        "unclosed parenthese in impl method params",
+                        "insert ')'",
+                        makeSourceLocation(methodNameToken)));
+                }
+                if (match(TokenType::RightParen))
+                {
+                    break;
+                }
+
+                if (!currentToken().isIdentifier())
+                {
+                    return std::unexpected(
+                        makeUnexpectTokenError("ImplStmt", "param name", currentToken()));
+                }
+
+                const Token  &pToken = consumeToken();
+                const String &pName  = srcManager.GetSub(pToken.index, pToken.length);
+
+                Expr *pType = nullptr;
+                if (match(TokenType::Colon))
+                {
+                    auto res = parseTypeExpr();
+                    if (!res)
+                        return std::unexpected(res.error());
+                    pType = *res;
+                }
+
+                PosParam *param = arena.Allocate<PosParam>(
+                    pName, pType, nullptr, makeSourceLocation(pToken));
+                fnParams.push_back(param);
+
+                if (match(TokenType::Comma))
+                {
+                    if (match(TokenType::RightParen))
+                        break; // 尾部逗号
+                }
+            }
+
+            // impl 方法不写返回类型，必须有函数体
+            BlockStmt *methodBody = nullptr;
+            if (currentToken().type == TokenType::LeftBrace)
+            {
+                auto bodyRes = parseBlockStmt();
+                if (!bodyRes)
+                    return std::unexpected(bodyRes.error());
+                methodBody = *bodyRes;
+            }
+            else
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("ImplStmt", "`{` for method body", currentToken()));
+            }
+
+            FnDefStmt *fnDef = arena.Allocate<FnDefStmt>(
+                false, methodName, fnParams, nullptr /* no return type */, methodBody,
+                makeSourceLocation(methodNameToken));
+            methods.push_back(fnDef);
         }
 
-        if (isEOF)
+        ImplStmt *implStmt = arena.Allocate<ImplStmt>(interfaceType, structType, methods, location);
+        return implStmt;
+    }
+
+    Result<Stmt *, Error> Parser::parseImportStmt()
+    {
+        SourceLocation location = makeSourceLocation(consumeToken()); // consume `import`
+
+        bool   isFileImport = false;
+        String path;
+
+        if (currentToken().type == TokenType::LiteralString)
         {
-            return nullptr;
+            // import "path/to/file.fig" — 文件导入
+            isFileImport = true;
+            const Token &strToken = consumeToken();
+            path = srcManager.GetSub(strToken.index, strToken.length);
+        }
+        else if (currentToken().isIdentifier())
+        {
+            // import std.io — Module 导入
+            isFileImport = false;
+            // 收集完整的路径: a.b.c
+            while (true)
+            {
+                const Token &tok = consumeToken();
+                path += srcManager.GetSub(tok.index, tok.length);
+                if (currentToken().type == TokenType::Dot)
+                {
+                    path += ".";
+                    consumeToken(); // consume `.`
+                }
+                else
+                {
+                    break;
+                }
+            }
+        }
+        else
+        {
+            return std::unexpected(
+                makeUnexpectTokenError("ImportStmt", "module path or file string", currentToken()));
         }
 
-        if (currentToken().type == TokenType::Semicolon)
-        {
-            return std::unexpected(Error(
-                ErrorType::SyntaxError,
-                "null statement is not allowed here",
-                "remove `;`",
-                makeSourceLocation(currentToken())));
-        }
-
-        const auto &expr_result = parseExpression();
-        if (!expr_result)
-        {
-            return std::unexpected(expr_result.error());
-        }
-        ExprStmt *exprStmt = arena.Allocate<ExprStmt>(*expr_result);
         if (!match(TokenType::Semicolon))
         {
             return std::unexpected(makeExpectSemicolonError());
         }
+
+        ImportStmt *importStmt = arena.Allocate<ImportStmt>(path, isFileImport, location);
+        return importStmt;
+    }
+
+    Result<Stmt *, Error> Parser::parseStatement()
+    {
+        StateProtector p(this, {State::Standby});
+
+        bool isPublic = match(TokenType::Public);
+
+        TokenType tt = currentToken().type;
+
+        
+        switch (tt)
+        {
+            case TokenType::LeftBrace: return parseBlockStmt();
+            case TokenType::If:        return parseIfStmt();
+            case TokenType::While:     return parseWhileStmt();
+            case TokenType::For:       return parseForStmt();
+            case TokenType::Import:    return parseImportStmt();
+            case TokenType::Interface: return parseInterfaceDef(isPublic);
+            case TokenType::Implement: return parseImpl();
+
+            case TokenType::Variable: return parseVarDecl(isPublic);
+            case TokenType::Const:    return parseConstDecl(isPublic);
+
+            case TokenType::Return:
+            {
+                return parseReturnStmt();
+            }
+
+            case TokenType::Function:
+            {
+                // 需要 lookahead: `func identifier` → 函数定义
+                //                 `func (` 或 `func {` → Lambda 表达式语句
+                if (peekToken().isIdentifier())
+                    return parseFnDefStmt(isPublic);
+                goto expr_stmt;
+            }
+
+            case TokenType::Struct:
+                return parseStructDef(isPublic);
+
+            case TokenType::Break:
+            {
+                consumeToken();
+                SourceLocation loc = makeSourceLocation(prevToken());
+                if (!match(TokenType::Semicolon))
+                    return std::unexpected(makeExpectSemicolonError());
+                return static_cast<Stmt *>(arena.Allocate<BreakStmt>(loc));
+            }
+
+            case TokenType::Continue:
+            {
+                consumeToken();
+                SourceLocation loc = makeSourceLocation(prevToken());
+                if (!match(TokenType::Semicolon))
+                    return std::unexpected(makeExpectSemicolonError());
+                return static_cast<Stmt *>(arena.Allocate<ContinueStmt>(loc));
+            }
+
+            case TokenType::EndOfFile:
+                return nullptr;
+
+            case TokenType::Semicolon:
+                return std::unexpected(Error(
+                    ErrorType::SyntaxError,
+                    "null statement is not allowed here",
+                    "remove `;`",
+                    makeSourceLocation(currentToken())));
+
+            default:
+                break;
+        }
+
+    expr_stmt:
+    {
+        // 表达式语句 (fallback)
+        const auto &expr_result = parseExpression();
+        if (!expr_result)
+            return std::unexpected(expr_result.error());
+        ExprStmt *exprStmt = arena.Allocate<ExprStmt>(*expr_result);
+        if (!match(TokenType::Semicolon))
+            return std::unexpected(makeExpectSemicolonError());
         return exprStmt;
     }
-}; // namespace Fig
\ No newline at end of file
+    }
+
+}; // namespace Fig
diff --git a/src/Parser/TypeExprParser.cpp b/src/Parser/TypeExprParser.cpp
index 34df7db..66f6ce3 100644
--- a/src/Parser/TypeExprParser.cpp
+++ b/src/Parser/TypeExprParser.cpp
@@ -1,8 +1,8 @@
 /*!
     @file src/Parser/TypeExprParser.cpp
-    @brief 类型表达式解析器实现：支持泛型与空安全
+    @brief 类型表达式解析器实现 — 类型即值，产生 Expr* 而非 TypeExpr*
     @author PuqiAR (im@puqiar.top)
-    @date 2026-03-08
+    @date 2026-06-06
 */
 
 #include <Parser/Parser.hpp>
@@ -49,38 +49,51 @@ namespace Fig
         return tp;
     }
 
-    // 解析基础命名类型与泛型: List<Int>
-    Result<TypeExpr *, Error> Parser::parseNamedTypeExpr()
+    
+    
+    Result<Expr *, Error> Parser::parseNamedTypeExpr()
     {
         StateProtector p(this, {State::ParsingNamedTypeExpr});
-        SourceLocation location = makeSourceLocation(currentToken());
 
-        DynArray<String> path;
-        while (true)
+        
+        if (!currentToken().isIdentifier())
         {
-            const Token  &tok  = consumeToken();
-            const String &name = srcManager.GetSub(tok.index, tok.length);
-            path.push_back(name);
-
-            if (match(TokenType::Dot))
-            {
-                if (!currentToken().isIdentifier())
-                    return std::unexpected(
-                        makeUnexpectTokenError("Type", "identifier", currentToken()));
-            }
-            else
-                break;
+            return std::unexpected(
+                makeUnexpectTokenError("TypeExpr", "type name", currentToken()));
         }
 
-        DynArray<TypeExpr *> arguments;
-        if (match(TokenType::Less)) // `<`
+        const Token  &firstTok  = consumeToken();
+        SourceLocation firstLoc = makeSourceLocation(firstTok);
+        const String &firstName = srcManager.GetSub(firstTok.index, firstTok.length);
+
+        IdentiExpr *ident = arena.Allocate<IdentiExpr>(firstName, firstLoc);
+        Expr       *base  = ident;
+
+        // a.b.c
+        while (match(TokenType::Dot))
         {
+            if (!currentToken().isIdentifier())
+            {
+                return std::unexpected(
+                    makeUnexpectTokenError("TypeExpr", "identifier after `.`", currentToken()));
+            }
+            const Token  &tok  = consumeToken();
+            const String &name = srcManager.GetSub(tok.index, tok.length);
+            SourceLocation loc = makeSourceLocation(tok);
+            base = arena.Allocate<MemberExpr>(base, name, loc);
+        }
+
+        // generic args
+        if (match(TokenType::Less))
+        {
+            DynArray<Expr *> args;
+
             while (true)
             {
                 auto result = parseTypeExpr();
                 if (!result)
                     return std::unexpected(result.error());
-                arguments.push_back(*result);
+                args.push_back(*result);
 
                 if (match(TokenType::Greater))
                     break; // `>`
@@ -88,12 +101,14 @@ namespace Fig
                     return std::unexpected(
                         makeUnexpectTokenError("TypeArgs", "'>' or ','", currentToken()));
             }
+
+            base = arena.Allocate<ApplyExpr>(base, std::move(args), firstLoc);
         }
 
-        return arena.Allocate<NamedTypeExpr>(path, arguments, location);
+        return base;
     }
 
-    Result<TypeExpr *, Error> Parser::parseFnTypeExpr()
+    Result<Expr *, Error> Parser::parseFnTypeExpr()
     {
         StateProtector p(this, {State::ParsingFnTypeExpr});
         SourceLocation location = makeSourceLocation(consumeToken()); // consume `func`
@@ -103,7 +118,7 @@ namespace Fig
                 makeUnexpectTokenError("FnTypeExpr", "lparen (", currentToken()));
         }
 
-        DynArray<TypeExpr *> paraTypes;
+        DynArray<Expr *> paraTypes;
 
         while (true)
         {
@@ -130,7 +145,7 @@ namespace Fig
             }
         }
 
-        TypeExpr *returnType = nullptr;
+        Expr *returnType = nullptr;
 
         if (match(TokenType::RightArrow)) // ->
         {
@@ -146,10 +161,10 @@ namespace Fig
         return fnTypeExpr;
     }
 
-    // 解析主入口: 处理 `?` 后缀
-    Result<TypeExpr *, Error> Parser::parseTypeExpr()
+    
+    Result<Expr *, Error> Parser::parseTypeExpr()
     {
-        TypeExpr *base = nullptr;
+        Expr *base = nullptr;
 
         if (currentToken().isIdentifier())
         {
@@ -174,10 +189,10 @@ namespace Fig
             return std::unexpected(makeUnexpectTokenError("TypeExpr", "name", currentToken()));
         }
 
-        // type (?)
+        // nullable
         if (currentToken().type == TokenType::Question) // ?
         {
-            base = arena.Allocate<NullableTypeExpr>(
+            base = arena.Allocate<NullableExpr>(
                 base, makeSourceLocation(consumeToken())); // consume `?`
         }
 
diff --git a/src/Sema/Analyzer.cpp b/src/Sema/Analyzer.cpp
index 6a96c6f..e2480be 100644
--- a/src/Sema/Analyzer.cpp
+++ b/src/Sema/Analyzer.cpp
@@ -678,7 +678,7 @@ namespace Fig
         return idx;
     }
 
-    Result<Type, Error> Analyzer::resolveTypeExpr(TypeExpr *texpr)
+    Result<Type, Error> Analyzer::resolveTypeExpr(Expr *texpr)
     {
         if (!texpr)
             return typeCtx.GetBasic(TypeTag::Any);
diff --git a/src/Sema/Analyzer.hpp b/src/Sema/Analyzer.hpp
index 15a9b1b..67f9cd2 100644
--- a/src/Sema/Analyzer.hpp
+++ b/src/Sema/Analyzer.hpp
@@ -32,7 +32,7 @@ namespace Fig
         // 核心递归查找：解决跨越函数边界的捕获问题
         Result<Symbol*, Error> resolveSymbolInternal(const String &name, const SourceLocation &loc, Scope* startScope);
 
-        Result<Type, Error> resolveTypeExpr(TypeExpr *texpr);
+        Result<Type, Error> resolveTypeExpr(Expr *texpr);
         Result<void, Error> pass1(Program *prog);
         Result<void, Error> resolveTypes(Program *prog); 
         Result<void, Error> checkBodies(Program *prog);  
diff --git a/tests/Parser/parser_comprehensive_test.fig b/tests/Parser/parser_comprehensive_test.fig
new file mode 100644
index 0000000..74d5a8e
--- /dev/null
+++ b/tests/Parser/parser_comprehensive_test.fig
@@ -0,0 +1,232 @@
+/* ==============================
+   Fig Parser Comprehensive Test
+   ============================== */
+
+// --- 单行注释 ---
+
+/* ---
+   多行注释
+   --- */
+
+// ─────────────────────────────────
+// 1. 变量声明 var
+// ─────────────────────────────────
+var x;                           // Any, 无初始化
+var a = 10;                      // 推断 Int
+var b: Int = 20;                 // 显式类型
+var c := 30;                     // 类型推断锁定
+var d: Int;                      // 显式类型，无初始化
+var e = "hello";                 // 推断 String
+var f = true;                    // 推断 Bool
+var g = null;                    // 推断 Null
+
+// ─────────────────────────────────
+// 2. 常量声明 const
+// ─────────────────────────────────
+const PI = 3.14159;              // 推断 Double
+const MAX: Int = 100;            // 显式类型
+const NAME := "Fig";             // 类型推断锁定
+const T: Double = 2.718;         // 显式类型
+
+// ─────────────────────────────────
+// 3. 函数定义 func
+// ─────────────────────────────────
+func noop() {}
+func add(a: Int, b: Int) -> Int { return a + b; }
+func greet(name: String) -> String { return "Hello " + name + "!"; }
+func quick(x) => x * 2;          // 箭头简写
+func noReturn() -> Null { return null; }
+
+// ─────────────────────────────────
+// 4. Lambda 表达式
+// ─────────────────────────────────
+var lambda1 = func(x, y) => x + y;
+var lambda2 = func(x: Int) { return x * x; };
+
+// ─────────────────────────────────
+// 5. 控制流 if / while / for
+// ─────────────────────────────────
+func testControlFlow() {
+    // if-else
+    if true { var z = 1; }
+    if (x > 0) { var z = 2; }
+    if a > 10 { return 1; }
+    else if a > 5 { return 2; }
+    else { return 3; }
+
+    // while
+    while a < 10 { a = a + 1; }
+    while (a > 0) { a = a - 1; }
+
+    // for (C风格，括号可选)
+    for var i = 0; i < 10; i = i + 1 { var _ = i; }
+    for (var j = 0; j < 5; j += 1) { var _ = j; }
+    for ; ; { break; }            // 无限循环
+
+    // break / continue
+    while true { break; }
+    while true { continue; }
+
+    return 0;
+}
+
+// ─────────────────────────────────
+// 6. 表达式运算符
+// ─────────────────────────────────
+func testOperators() -> Int {
+    var r = 0;
+
+    // 算术
+    r = 1 + 2;
+    r = 3 - 1;
+    r = 2 * 3;
+    r = 6 / 2;
+    r = 7 % 3;
+    r = 2 ** 3;                    // 幂运算
+
+    // 比较
+    var b1 = 1 == 1;
+    var b2 = 1 != 2;
+    var b3 = 1 < 2;
+    var b4 = 2 > 1;
+    var b5 = 1 <= 1;
+    var b6 = 2 >= 1;
+
+    // 逻辑
+    var l1 = true and false;
+    var l2 = true or false;
+    var l3 = not true;
+    var l4 = true && false;        // &&
+    var l5 = true || false;        // ||
+
+    // 复合赋值
+    r += 1;
+    r -= 1;
+    r *= 2;
+    r /= 2;
+    r %= 1;
+    r ^= 1;
+
+    // 位运算
+    var w1 = 1 & 2;
+    var w2 = 1 | 2;
+    var w3 = 1 ^ 2;
+    var w4 = ~1;
+    var w5 = 1 << 2;
+    var w6 = 4 >> 1;
+
+    // 前后缀 ++/--
+    var p = 0;
+    var pre = ++p;
+    var post = p--;
+    var n = --p;
+
+    // 前缀取反
+    var neg = -100;
+    var notExpr = not true;
+
+    // 三元
+    var t = a > 5 ? 1 : 0;
+
+    // 成员访问
+    var m = someObj.field;
+
+    // 类型检查 / 转换
+    var check = x is Int;
+    var cast = x as String;
+
+    // 索引
+    var idx = arr[0];
+
+    // 函数调用
+    var callRes = add(1, 2);
+
+    // 分组
+    var grouped = (1 + 2) * 3;
+
+    return r;
+}
+
+// ─────────────────────────────────
+// 7. struct 结构体
+// ─────────────────────────────────
+struct Point {
+    public x: Int;
+    public y: Int;
+
+    public func toString() -> String {
+        return "(" + "x" + "," + "y" + ")";
+    }
+}
+
+struct Person {
+    name: String;
+    age: Int = 18;                 // 默认值
+
+    public func getName() -> String {
+        return name;
+    }
+}
+
+// ─────────────────────────────────
+// 8. new 表达式
+// ─────────────────────────────────
+func testNewExpr() {
+    var p1 = new Point{1, 2};                  // 位置参数
+    var p2 = new Point{x: 2, y: 3};            // 命名参数
+    var xx = 114;
+    var yy = 514;
+    var p3 = new Point{yy, xx};                // 简写
+    var p4 = new Point{};                      // 空构造
+}
+
+// ─────────────────────────────────
+// 9. interface 接口
+// ─────────────────────────────────
+interface Drawable {
+    func draw() -> String;
+    func getLayer() -> Int;
+}
+
+interface Printable {
+    func toString() -> String;
+    func getVersion() -> Int {
+        return 1;
+    }
+}
+
+// ─────────────────────────────────
+// 10. impl 实现
+// ─────────────────────────────────
+struct Circle {
+    public radius: Double;
+}
+
+impl Drawable for Circle {
+    func draw() {
+        return "circle";
+    }
+    func getLayer() {
+        return 0;
+    }
+}
+
+// ─────────────────────────────────
+// 11. import 导入
+// ─────────────────────────────────
+import std.io;
+import "path/to/file.fig";
+
+// ─────────────────────────────────
+// 12. 闭包与嵌套函数
+// ─────────────────────────────────
+func outer(x: Int) -> Function {
+    func inner(n: Int) -> Int {
+        return n * x;
+    }
+    return inner;
+}
+
+var closureMaker = func(factor: Int) {
+    return func(n) => n * factor;
+};