修复对map多级指针的解析，修改文档

Author: liu-cn

README.md

@@ -718,7 +718,14 @@ func main() {
 	fmt.Println(string(marshal)) //以下是官方的json解析输出结果：可以看到所有的字段都被解析了出来
 	//{"uid":1,"nickname":"boyan","avatar":"avatar","sex":1,"vip_end_time":"2023-03-06T23:11:22.622693+08:00","price":"999.9"}
 
-  //用法：filter.SelectMarshal("select里的一个场景",这里可以是slice/array/struct/pointer/map)
+	//用法：filter.Select("select里的一个场景",这里可以是slice/array/struct/pointer/map)
+	article:=filter.Select("article", user)
+	articleBytes, _ := json.Marshal(article)
+	fmt.Println(string(articleBytes)) //以下是通过json-filter 过滤后的json，此输出是article接口下的json
+	//{"avatar":"avatar","nickname":"boyan","uid":1}
+	
+  //filter.SelectMarshal 是一个方便测试查看的方法，先过滤，然后再编码成json字符串返回，有错误直接panic，三部操作一气呵成，适合测试查看等
+  //下面为了方便演示，将使用SelectMarshal api来进行
 	fmt.Println(filter.SelectMarshal("article", user).MustJSON()) //以下是通过json-filter 过滤后的json，此输出是article接口下的json
 	//{"avatar":"avatar","nickname":"boyan","uid":1}
 
@@ -767,7 +774,8 @@ omit则反之，标记的字段会被排除。
 这时候你需要调用
 
 ```go
-f:=filter.OmitMarshal("chat",el) //这时Nickname字段就被排除掉了。
+f:=filter.Omit("chat",el) //这时Nickname字段就被排除掉了。
+f:=filter.OmitMarshal("chat",el) //同样是是一气呵成的操作，将结构体编码后返回一个对象，可以选择对象的任意形态
 ```
 
 ##### omitempty零值忽略

filter/omit_encode.go

@@ -124,8 +124,10 @@ TakePointerValue: //取指针的值
 		}
 
 	case reflect.Map:
+	takeVMap:
 		if valueOf.Kind() == reflect.Ptr {
 			valueOf = valueOf.Elem()
+			goto takeVMap
 		}
 		keys := valueOf.MapKeys()
 		if len(keys) == 0 { //空map情况下解析为{}
@@ -134,14 +136,14 @@ TakePointerValue: //取指针的值
 		}
 		for i := 0; i < len(keys); i++ {
 			mapIsNil := false
-		takeValMap:
 			val := valueOf.MapIndex(keys[i])
+		takeValMap:
 			if val.Kind() == reflect.Ptr {
 				if val.IsNil() {
 					mapIsNil = true
 					continue
 				} else {
-					val = valueOf.MapIndex(keys[i]).Elem()
+					val = val.Elem()
 					goto takeValMap
 				}
 			}

filter/select_encode.go

@@ -123,8 +123,10 @@ TakePointerValue: //取指针的值
 		}
 
 	case reflect.Map:
+	takeVMap:
 		if valueOf.Kind() == reflect.Ptr {
 			valueOf = valueOf.Elem()
+			goto takeVMap
 		}
 		keys := valueOf.MapKeys()
 		if len(keys) == 0 { //空map情况下解析为{}
@@ -133,14 +135,14 @@ TakePointerValue: //取指针的值
 		}
 		for i := 0; i < len(keys); i++ {
 			mapIsNil := false
-		takeValMap:
 			val := valueOf.MapIndex(keys[i])
+		takeValMap:
 			if val.Kind() == reflect.Ptr {
 				if val.IsNil() {
 					mapIsNil = true
 					continue
 				} else {
-					val = valueOf.MapIndex(keys[i]).Elem()
+					val = val.Elem()
 					goto takeValMap
 				}
 			}

test/main.go

@@ -0,0 +1,6 @@
+package main
+
+func main() {
+	TestSlice()
+	TestMap()
+}

test/map.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"fmt"
+	"github.com/liu-cn/json-filter/filter"
+)
+
+type Map struct {
+	//Name string              `json:"name,select(article)"`
+	//Age  int                 `json:"age,select(article)"`
+	//ID   int                 `json:"id,select(article)"`
+	M   map[string]**string   `json:"m,select(test)"`
+	T   map[string]**string   `json:"t,select(),omit(test)"`
+	MP  *map[string]**string  `json:"mp,select(test)"`
+	MPP **map[string]**string `json:"mpp,select(test)"`
+}
+
+func TestMap() {
+
+	str := "c++从研发到脱发"
+	ptr := &str
+	maps := make(map[string]**string)
+	maps["test"] = &ptr
+	mp := &maps
+	mpp := &mp
+	fmt.Println("select:", filter.SelectMarshal("test", Map{M: maps, T: maps, MP: mp, MPP: mpp}).MustJSON())
+	//	{"m":{"test":"c++从研发到脱发"},"mp":{"test":"c++从研发到脱发"},"mpp":{"test":"c++从研发到脱发"}}
+
+	fmt.Println("omit:", filter.OmitMarshal("test", Map{M: maps, T: maps, MP: mp, MPP: mpp}).MustJSON())
+	//{"m":{"test":"c++从研发到脱发"},"mp":{"test":"c++从研发到脱发"},"mpp":{"test":"c++从研发到脱发"}}
+}

test/slice.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/liu-cn/json-filter/filter"
+)
+
+type Slice struct {
+	Slices   []**string   `json:"slices,select(test)"`
+	Test     []**string   `json:"test,select(),omit(test)"`
+	SliceP   *[]**string  `json:"slice_p,select(test)"`
+	SlicesPP **[]**string `json:"slices_pp,select(test)"`
+}
+
+func TestSlice() {
+	s := "值"
+	p := &s
+
+	slice := make([]**string, 0, 5)
+	slice = append(slice, &p)
+	pp := &slice
+	ppp := &pp
+
+	test := Slice{
+		Slices:   slice,
+		SliceP:   pp,
+		SlicesPP: ppp,
+		Test:     slice,
+	}
+
+	fmt.Println("slice select:", filter.SelectMarshal("test", test).MustJSON())
+	//{"slice_p":["值"],"slices":["值"],"slices_pp":["值"]}
+	fmt.Println("slice omit:", filter.OmitMarshal("test", test).MustJSON())
+	//{"slice_p":["值"],"slices":["值"],"slices_pp":["值"]}
+
+	marshal, _ := json.Marshal(test)
+	fmt.Println("原生slice json 解析", string(marshal))
+	//{"slices":["值"],"test":["值"],"slice_p":["值"],"slices_pp":["值"]}
+}