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Merge pull request #782 from y4h2/parse-config
Parse AST to generate config document
This commit is contained in:
commit
b168005893
185
parser/parser.go
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185
parser/parser.go
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@ -0,0 +1,185 @@
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package beeParser
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import (
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"encoding/json"
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"errors"
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"go/ast"
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"go/importer"
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"go/parser"
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"go/token"
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"go/types"
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)
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// StructField defines struct field
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type StructField struct {
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Name string
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Type types.Type
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NestedType *StructNode
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Comment string
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Doc string
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Tag string
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}
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// Key returns the key of the field
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func (sf *StructField) Key() string {
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return sf.Name
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}
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// Value returns the value of the field
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// if the field contains nested struct, it will return a nested result
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func (sf *StructField) Value() interface{} {
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if sf.NestedType != nil {
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return sf.NestedType.ToKV()
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}
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return ""
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}
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// StructNode defines struct node
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type StructNode struct {
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Name string
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Fields []*StructField
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}
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// ToKV transfers struct to key value pair
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func (sn *StructNode) ToKV() map[string]interface{} {
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value := map[string]interface{}{}
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for _, field := range sn.Fields {
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value[field.Key()] = field.Value()
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}
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return value
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}
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// StructParser parses structs in given file or string
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type StructParser struct {
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MainStruct *StructNode
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Info types.Info
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}
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// NewStructParser is the constructor of StructParser
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// filePath and src follow the same rule with go/parser.ParseFile
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// If src != nil, ParseFile parses the source from src and the filename is only used when recording position information. The type of the argument for the src parameter must be string, []byte, or io.Reader. If src == nil, ParseFile parses the file specified by filename.
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// rootStruct is the root struct we want to use
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func NewStructParser(filePath string, src interface{}, rootStruct string) (*StructParser, error) {
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fset := token.NewFileSet()
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f, err := parser.ParseFile(fset, filePath, src, parser.ParseComments)
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if err != nil {
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return nil, err
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}
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info := types.Info{
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Types: make(map[ast.Expr]types.TypeAndValue),
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Defs: make(map[*ast.Ident]types.Object),
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Uses: make(map[*ast.Ident]types.Object),
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}
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conf := types.Config{
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Importer: importer.ForCompiler(fset, "source", nil),
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}
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_, err = conf.Check("src", fset, []*ast.File{f}, &info)
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if err != nil {
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return nil, err
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}
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cg := &StructParser{
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Info: info,
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}
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ast.Inspect(f, func(n ast.Node) bool {
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// ast.Print(nil, n)
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ts, ok := n.(*ast.TypeSpec)
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if !ok || ts.Type == nil {
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return true
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}
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structName := ts.Name.Name
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if structName != rootStruct {
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return true
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}
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s, ok := ts.Type.(*ast.StructType)
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if !ok {
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return true
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}
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cg.MainStruct = cg.ParseStruct(structName, s)
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return false
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})
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if cg.MainStruct == nil {
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return nil, errors.New("non-exist root struct")
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}
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return cg, nil
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}
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func (cg *StructParser) ToJSON() ([]byte, error) {
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value := cg.MainStruct.ToKV()
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return json.MarshalIndent(value, "", " ")
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}
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// ParseField parses struct field in nested way
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func (cg *StructParser) ParseField(field *ast.Field) *StructField {
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// ast.Print(nil, field)
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fieldName := field.Names[0].Name
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fieldType := cg.Info.TypeOf(field.Type)
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fieldTag := ""
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if field.Tag != nil {
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fieldTag = field.Tag.Value
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}
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fieldComment := ""
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if field.Comment != nil {
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fieldComment = field.Comment.Text()
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}
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fieldDoc := ""
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if field.Doc != nil {
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fieldDoc = field.Doc.Text()
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}
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var nestedStruct *StructNode
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if s, isInlineStruct := field.Type.(*ast.StructType); isInlineStruct {
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nestedStruct = cg.ParseStruct("", s)
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}
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if _, isNamedStructorBasic := field.Type.(*ast.Ident); isNamedStructorBasic && field.Type.(*ast.Ident).Obj != nil {
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ts, ok := field.Type.(*ast.Ident).Obj.Decl.(*ast.TypeSpec)
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if !ok || ts.Type == nil {
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return nil
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}
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s, ok := ts.Type.(*ast.StructType)
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if !ok {
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return nil
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}
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nestedStruct = cg.ParseStruct(ts.Name.Name, s)
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}
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// fieldType.(*types.Basic) // basic type
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// *ast.ArrayType:
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// *ast.MapType:
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// *ast.SelectorExpr: // third party
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return &StructField{
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Name: fieldName,
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Type: fieldType,
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Tag: fieldTag,
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Comment: fieldComment,
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Doc: fieldDoc,
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NestedType: nestedStruct,
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}
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}
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// ParseStruct parses struct in nested way
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func (cg *StructParser) ParseStruct(structName string, s *ast.StructType) *StructNode {
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fields := []*StructField{}
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for _, field := range s.Fields.List {
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parsedField := cg.ParseField(field)
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if parsedField != nil {
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fields = append(fields, parsedField)
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}
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}
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return &StructNode{
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Name: structName,
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Fields: fields,
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}
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}
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60
parser/parser_test.go
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60
parser/parser_test.go
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@ -0,0 +1,60 @@
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package beeParser
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import (
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"fmt"
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"log"
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)
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func ExampleStructParser() {
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const src = `
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package p
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import (
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"net/http"
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)
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type StructB struct {
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Field1 string
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}
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type StructA struct {
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Field1 string
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Field2 struct{
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a string
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b string
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}
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Field3 []string
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Field4 map[string]string
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Field5 http.SameSite
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Field6 func(int)
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Field7 StructB
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}
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`
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cg, err := NewStructParser("src.go", src, "StructA")
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if err != nil {
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log.Fatal(err)
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}
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b, err := cg.ToJSON()
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if err != nil {
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log.Fatal(err)
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}
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fmt.Println(string(b))
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// Output:
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// {
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// "Field1": "",
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// "Field2": {
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// "a": "",
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// "b": ""
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// },
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// "Field3": "",
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// "Field4": "",
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// "Field5": "",
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// "Field6": "",
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// "Field7": {
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// "Field1": ""
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// }
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// }
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}
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