refactor(core): 优化exists函数实现和代码结构

- 将逻辑运算符从 'or' 替换为 '||' 以提高可读性
- 重新排列ClosureBox类成员变量顺序
- 添加基本类型的exists函数重载（Int、Float、Bool）
- 实现Variant类型的exists函数并处理null和undef情况
- 添加单元测试验证exists函数的基本功能

Author: matyhtf

include/phpx_helper.h

@@ -95,6 +95,22 @@ static inline Bool empty(const Variant &v) {
     return !v.toBool();
 }
 
+static inline bool exists(Int v) {
+    return true;
+}
+
+static inline bool exists(Float v) {
+    return true;
+}
+
+static inline bool exists(Bool v) {
+    return true;
+}
+
+static inline Bool exists(const Variant &v) {
+    return !(v.isNull() || v.isUndef());
+}
+
 static inline void move(Int v, zval *retval) {
     ZVAL_LONG(retval, v);
 }

src/core/base.cc

@@ -523,7 +523,7 @@ bool empty(const Variant &v, const std::initializer_list<std::pair<Operation, co
 
 bool exists(const Variant &v, const std::initializer_list<std::pair<Operation, const Variant>> &list) {
     Variant tmp = v;
-    if (tmp.isNull() or tmp.isUndef()) {
+    if (tmp.isNull() || tmp.isUndef()) {
         return false;
     }
 

src/core/closure.cc

@@ -28,8 +28,8 @@ class ClosureBox : public Box {
   public:
     Object this_;
     ClosureFn fn_;
-    zend_function *zf_;
     Array vars_;
+    zend_function *zf_;
 
     ClosureBox(const ClosureFn &fn, const Object &_this, const Array &vars, zend_function *zf) {
         fn_ = fn;

tests/src/exists.cpp

@@ -4,6 +4,16 @@
 
 using namespace php;
 
+TEST(exists, basic) {
+    ASSERT_TRUE(exists(100L));
+    ASSERT_TRUE(exists(100.1002));
+    ASSERT_TRUE(exists(true));
+    ASSERT_TRUE(exists(false));
+    ASSERT_FALSE(exists(null));
+    var v(undef());
+    ASSERT_FALSE(exists(v));
+}
+
 TEST(exists, null) {
     var v1;
     ASSERT_FALSE(exists(v1, {}));