feat: 添加If语句及块语句解析支持

src/Ast/Stmt/IfStmt.hpp

@@ -0,0 +1,69 @@
+/*!
+    @file src/Ast/Stmt/IfStmt.hpp
+    @brief IfStmt定义
+    @author PuqiAR (im@puqiar.top)
+    @date 2026-02-20
+*/
+
+#pragma once
+
+#include <Ast/Base.hpp>
+
+namespace Fig
+{
+    struct ElseIfStmt final : public Stmt
+    {
+        Expr      *cond;
+        BlockStmt *consequent;
+
+        ElseIfStmt()
+        {
+            type = AstType::ElseIfStmt;
+        }
+
+        ElseIfStmt(Expr *_cond, BlockStmt *_consequent, SourceLocation _location) :
+            cond(_cond), consequent(_consequent)
+        {
+            type     = AstType::ElseIfStmt;
+            location = std::move(_location);
+        }
+
+        virtual String toString() const override
+        {
+            return std::format("<ElseIf ({}) then {}>", cond->toString(), consequent->toString());
+        }
+    };
+
+    struct IfStmt final : public Stmt
+    {
+        Expr                  *cond;
+        BlockStmt             *consequent;
+        DynArray<ElseIfStmt *> elifs;
+        BlockStmt             *alternate;
+
+        IfStmt()
+        {
+            type = AstType::IfStmt;
+        }
+
+        IfStmt(Expr               *_cond,
+            BlockStmt             *_consequent,
+            DynArray<ElseIfStmt *> _elifs,
+            BlockStmt             *_alternate,
+            SourceLocation         _location) :
+            cond(_cond), consequent(_consequent), elifs(std::move(_elifs)), alternate(_alternate)
+        {
+            type     = AstType::IfStmt;
+            location = std::move(_location);
+        }
+
+        virtual String toString() const override
+        {
+            return std::format("<If ({}) then {}, else if * {}, else {}>",
+                cond->toString(),
+                consequent->toString(),
+                elifs.size(),
+                alternate->toString());
+        }
+    };
+}; // namespace Fig