feat(reflect): 添加反射相关功能和Purchase结构体

- 新增createPointerType和followPointerType函数处理指针类型- 实现transformString函数用于字符串转换- 添加checkElemType函数检查数组或切片元素类型
- 实现setValue函数用于设置数组或切片元素值
- 新增main15-main18函数演示反射操作
- 添加Purchase结构体组合Product和Customer类型

27-reflection/reflection/main.go

@@ -11,4 +11,9 @@ func main() {
 	main12()
 	main13()
 	main14()
+
+	main15()
+	main16()
+	main17()
+	main18()
 }

27-reflection/reflection/re2.go

@@ -0,0 +1,120 @@
+package main
+
+import (
+	"reflect"
+	"strings"
+)
+
+func createPointerType(t reflect.Type) reflect.Type {
+	return reflect.PointerTo(t)
+}
+
+func followPointerType(t reflect.Type) reflect.Type {
+	if t.Kind() == reflect.Ptr {
+		return t.Elem()
+	}
+	return t
+}
+
+func main15() {
+	Printfln("\nmain15:")
+	name := "Alice"
+
+	t := reflect.TypeOf(name)
+	Printfln("Original Type: %v", t)
+
+	pt := createPointerType(t)
+	Printfln("Pointer Type: %v", pt)
+	Printfln("Pointer Type: %v", followPointerType(pt))
+}
+
+var stringPtrType = reflect.TypeOf((*string)(nil))
+
+func transformString(val interface{}) {
+	elemValue := reflect.ValueOf(val)
+	if elemValue.Type() == stringPtrType {
+		if elemValue.CanAddr() {
+			Printfln("Can address pointer addr: %v", elemValue.Addr())
+		}
+		elem := elemValue.Elem()
+		if elem.CanAddr() {
+			Printfln("Can address Follow pointer addr: %v", elem.Addr())
+		}
+		upperStr := strings.ToUpper(elem.String())
+		if elem.CanSet() {
+			elem.SetString(upperStr)
+		}
+	}
+}
+
+func main16() {
+	Printfln("\nmain16:")
+
+	name := "Alice"
+	transformString(&name)
+	Printfln("Follow pointer value:  %v  addr: %p", name, &name)
+
+}
+
+func checkElemType(val interface{}, arrOrSlice interface{}) bool {
+	elemType := reflect.TypeOf(val)
+	arrOrSliceType := reflect.TypeOf(arrOrSlice)
+
+	return (arrOrSliceType.Kind() == reflect.Array ||
+		arrOrSliceType.Kind() == reflect.Slice) &&
+		arrOrSliceType.Elem() == elemType
+}
+
+func main17() {
+	Printfln("\nmain17:")
+
+	name := "Alice"
+	city := "London"
+	hobby := "Running"
+
+	slice := []string{name, city, hobby}
+	array := [3]string{name, city, hobby}
+
+	Printfln("Slice (string): %v", checkElemType("testString", slice))
+	Printfln("Array (string): %v", checkElemType("testString", array))
+	Printfln("Slice (int): %v", checkElemType(10, slice))
+}
+
+func setValue(arrayOrSlice interface{}, index int, replacement interface{}) {
+	arrayOrSliceVal := reflect.ValueOf(arrayOrSlice)
+	replacementVal := reflect.ValueOf(replacement)
+	if arrayOrSliceVal.Kind() == reflect.Slice {
+		elemVal := arrayOrSliceVal.Index(index)
+		if elemVal.CanSet() {
+			elemVal.Set(replacementVal)
+		}
+	} else if arrayOrSliceVal.Kind() == reflect.Ptr &&
+		arrayOrSliceVal.Elem().Kind() == reflect.Array &&
+		arrayOrSliceVal.Elem().CanSet() {
+		elemVal := arrayOrSliceVal.Elem().Index(index)
+		if elemVal.CanSet() {
+			elemVal.Set(replacementVal)
+		}
+	}
+}
+
+func main18() {
+	Printfln("\nmain17:")
+
+	name := "Alice"
+	city := "London"
+	hobby := "Running"
+
+	slice := []string{name, city, hobby}
+	array := [3]string{name, city, hobby}
+
+	Printfln("Original slice:%v", slice)
+	newCity := "Paris"
+	setValue(slice, 1, newCity)
+	Printfln("Modified slice:%v", slice)
+
+	Printfln("Original array:%v", array)
+	newCity = "Rome"
+	setValue(&slice, 1, newCity)
+	Printfln("Modified array:%v", array)
+}

27-reflection/reflection/types.go

@@ -13,3 +13,10 @@ type Payment struct {
 	Currency string
 	Amount   float64
 }
+
+type Purchase struct {
+	Product
+	Customer
+	Total   float64
+	taxRate float64
+}