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Go及AST毛中元仁勻化
陔仄中汁奈伙毛釬月
歹井戶引今夫欠

歹井戶引今夫欠 @vvakame
TypeScript
Masahiro Wakame
De?nitelyTyped
appengine
photo from golang.org/doc/gopher/

戶氏升中仇午反仄凶仁卅中
掞分勻化公丹允月
偃分勻化公丹允月

encoding/json
play.golang.org/p/T9uO25D2xz
＃
?
type Game struct {?
ID int64 `json:"id"`?
Title string `json:"title"`?
Price int `json:"price"`?
InDevelopment bool `json:"inDevelopment"`?
ShippedAt time.Time `json:"shippedAt"`?
}?
?
func main() {?
game := &Game{?
ID: 1,?
Title: "Splatoon",?
Price: 5700,?
InDevelopment: false,?
}?
b, _ := json.Marshal(game)?
fmt.Println(string(b))?
}

encoding/json
＃
?
type Game struct {?
ID int64 `json:"id"`?
Title string `json:"title"`?
Price int `json:"price"`?
InDevelopment bool `json:"inDevelopment"`?
ShippedAt time.Time `json:"shippedAt"`?
}?
?
func main() {?
game := &Game{?
ID: 1,?
Title: "Splatoon",?
Price: 5700,?
InDevelopment: false,?
}?
b, _ := json.Marshal(game)?
}
忒𤩸五ㄐˋ
淏𠸎井ㄐˋㄐˋ
戶氏升中
※ 寯元月及咭木月
typo月

jwg 釬勻凶
//go:generate jwg -output model_json.go .?
package sample?
?
＃
?
// +jwg?
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
ShippedAt time.Time?
}?
?
func main() {?
game := &Game{?
ID: 1, Title: "Splatoon", Price: 5700, InDevelopment: false,?
}?
jsonObj, _ := NewGameJsonBuilder().AddAll().Convert(game)?
b, _ := json.Marshal(jsonObj)?
}
jwg = Json Wrapper Generator

//go:generate jwg -output model_json.go .?
package sample?
?
＃
?
// +jwg?
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}?
?
func main() {?
game := &Game{?
ID: 1, Title: "Splatoon", Price: 5700, InDevelopment: false,?
}?
jsonObj, _ := NewGameJsonBuilder().AddAll().Convert(game)?
}
go generate 妏丹ㄐ
戊丟件玄卞正弘𤩸仁(㻢𨃨帊�卅升卅中ㄐ
汜傖仄凶戊奈玉瞳蚚分ㄐ
jwg 釬勻凶

赻�汜傖ㄐ
type GameJson struct {?
ID int64 `json:"id,omitempty"`?
Title string `json:"title,omitempty"`?
Price int `json:"price,omitempty"`?
InDevelopment bool `json:"inDevelopment,omitempty"`?
ShippedAt time.Time `json:"shippedAt,omitempty"`?
}
㜭

公及坻ㄐ
type GameJson
func (orig *GameJson) Convert() (*Game, error)
type GameJsonBuilder
func NewGameJsonBuilder() *GameJsonBuilder
func (b *GameJsonBuilder) Add(info *GamePropertyInfo) *GameJsonBuilder
func (b *GameJsonBuilder) AddAll() *GameJsonBuilder
func (b *GameJsonBuilder) Convert(orig *Game) (*GameJson, error)
func (b *GameJsonBuilder) ConvertList(orig []*Game) (GameJsonList, error)
func (b *GameJsonBuilder) Marshal(orig *Game) ([]byte, error)
func (b *GameJsonBuilder) Remove(info *GamePropertyInfo) *GameJsonBuilder
type GameJsonList
func (jsonList GameJsonList) Convert() ([]*Game, error)
type GamePropertyDecoder
type GamePropertyEncoder
type GamePropertyInfo *JsonBuilder
*Property(De|En)coder
*PropertyInfo

Web API釬傖蚚
play.golang.org/p/5wYA62Njvn
func (b *GameJsonBuilder) AddSite() *GameJsonBuilder {?
b.AddAll()?
b.Remove(b.ID) // ID反囀窒ロ�卅及匹中日卅中?
b.Price.Encoder = func(src *Game, dest *GameJson) error {?
if !src.InDevelopment {?
dest.Price = src.Price // 嶱逃笢元扎卅中媆分仃�跡毛堤允方ㄐ?
}?
return nil?
}?
?
return b?
}?
?
func main() {?
game := &Game{?
ID: 2, Title: "Secret of Yaba", Price: 9999, InDevelopment: true,?
}?
jsonObj, _ := NewGameJsonBuilder().AddSite().Convert(game)?
}
{
"title":"Secret of Yaba§,
※inDevelopment":true,
※shippedAt":"0001-01-01T00:00:00Z"
}
灍俴磐彆↙

仇及嶲鼠嶱仄引仄凶ㄐ
汜傖戊奈玉反杻卞甡湔卅仄

翋�
? 戊奈玉汜傖 is 晞瞳
? Go分午Generics卅中仄戊奈玉�尹互切
? 戊件由奶伙媆民尼永弁及塋𨫆ㄐ
? 恅趼蹈匹硌隅午井媆測綈木分方友‵
? 啋戊奈玉↙犯奈正趙↙樓馱↙汜傖ㄐ
? 引內反末奈旦戊奈玉毛賤昴仄卅中午ㄐ

淏�桶政匹薉�月
http://play.golang.org/p/fsOl7CcjgB
package main?
?
import (?
"fmt"?
"regexp"?
)?
?
func main() {?
code := `?
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}?
`?
?
re:=regexp.MustCompile(`s*types+([a-zA-Z]+)s+structs+{n(?:s*([a-zA-Z0-9]+)s+([a-zA-Z0-9.]+)s*n)*s*}`)?
result := re.FindAllStringSubmatch(code,-1)?
fmt.Printf("%#v", result)?
}

AST毛魂蚚允月
? AST = Abstract Syntax Tree
? 掛懂反戊件由奶仿囀窒及笢嶲桶政
? 末奈旦戊奈玉毛犯奈正午仄化妏尹月ㄐ
? 戊奈玉賤昴反仿奶皮仿伉卞￤六方丹ㄐ
? 賤昴摽及戊奈玉瞎蕾卞�癩匹五月ㄐ

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast = go/ast package
ast.GenDecl

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast.GenDecl
ast.TypeSpec
type (?
A struct {?
Foo string?
}?
B struct {?
Bar string?
}?
)
仇丹中丹�楊手丐月(窕中

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast.GenDecl
ast.TypeSpec
ast.Ident

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast.GenDecl
ast.TypeSpec
ast.Ident
ast.StructType

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast.GenDecl
ast.TypeSpec
ast.Ident
ast.StructType
ast.FieldList

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast.GenDecl
ast.TypeSpec
ast.Ident
ast.StructType
ast.FieldList
ast.Field type A struct {?
Foo, Bar string?
}
仇丹中丹�楊手丐月(窕中

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast.GenDecl
ast.TypeSpec
ast.Ident
ast.StructType
ast.FieldList
ast.Field
ast.Ident

Game struct ↙ AST
type Game struct {?
ID int64?
Title string?
Price int?
InDevelopment bool?
}
ast.GenDecl
ast.TypeSpec
ast.Ident
ast.StructType
ast.FieldList
ast.Field
ast.Ident
ast.Ident

AST↙戊奈玉汜傖
␟��␟
ˇ?恅趼蹈瞎心蕾化薉�月?ˉ
�Y^Y^Y^Y^Y^Y^Y^Y^Y^Y^Y�
引元井
引元分

嶱逃及戊汁午�婖
仇仇匹反﹜struct掂心龰曰↙
仿永由汜傖及霜木卞篇勻化賤掊允月

汁奈伙嶱逃及霜木
1. �I燴�砓(及struct)毛𢜪戶月
2. 戊奈玉汜傖磐彆毛忒𤩸五允月
?靡ゴ毛辻迮腔卞蕉尹化勾仃方丹
3. 斛猁卅偃倛宒及犯奈正�婖毛偞�允月
?AST井日龰木月井ˋ祥逋反卅中井ˋ
?倰ロ�龰木卅仁化釓中由正奈件丐月
4. 薉�勻化AST龰勻化劐𡥼仄化汜傖�I燴𤩸仁

Go戊奈玉及�婖
// generated by jwg -output model_json.go .; DO NOT EDIT?
?
package sample?
?
import (?
"encoding/json"?
"time"?
)?
?
// for Game?
}?
PackageClause
ImportDecl
TopLevelDecl

偃倛宒互斛猁卅燴蚕
// generated by jwg -output model_json.go .; DO NOT EDIT?
?
package sample?
?
import (?
"encoding/json"?
"time"?
)?
?
// for Game?
}?
淏仄中PackageClause及汜傖卞反﹜
TopLevelDecl汜傖磐彆及參挍互斛猁ㄐ etc..

測桶腔卅偃倛宒
? Source (汜傖磐彆末奈旦�极)
? Struct (汜傖允月struct1�煦)
? Field (∥及?eld1�煦)
? Tag (∥卞葆扽允月tagロ�)

jwg及�磁
// BuildStruct represents source code of assembling..?
type BuildSource struct {?
g *genbase.Generator?
pkg *genbase.PackageInfo?
typeInfos genbase.TypeInfos?
?
Structs []*BuildStruct?
}?
?
// BuildStruct represents struct of assembling..?
type BuildStruct struct {?
parent *BuildSource?
typeInfo *genbase.TypeInfo?
?
Fields []*BuildField?
}?
?
// BuildField represents field of BuildStruct.?
type BuildField struct {?
parent *BuildStruct?
fieldInfo *genbase.FieldInfo?
?
Name string?
Embed bool?
Tag *BuildTag?
}?
?
// BuildTag represents tag of BuildField.?
type BuildTag struct {?
field *BuildField?
?
Name string?
Ignore bool // e.g. Secret string `json:"-"`?
DoNotEmit bool // e.g. Field int `json:",omitempty"`?
String bool // e.g. Int64String int64 `json:",string"`?
}

genbase及仍畿賡
? 3勾幻升戊奈玉汜傖汁奈伙釬勻凶
? 隅倛�I燴及湔婓卞𠸎互勾仁
? AST掂心煋心
? 硌隅今木凶or正弘葆五struct及�摩
? import曆及奪燴
? 戊奈玉瞎心蕾化?白巧奈穴永玄
? 公及坻晞瞳憝杅午井
github.com/favclip/genbase
統蕉ㄩtypewriter

公仄化𠸎磁
func (st *BuildStruct) emit(g *genbase.Generator) error {?
g.Printf("// for %sn", st.Name())?
?
// generate FooJson struct from Foo struct?
g.Printf("type %sJson struct {n", st.Name())?
for _, field := range st.Fields {?
if field.Tag.Ignore {?
continue?
}?
postfix := ""?
if field.WithJWG() {?
postfix = "Json"?
}?
tagString := field.Tag.TagString()?
if tagString != "" {?
tagString = fmt.Sprintf("`%s`", tagString)?
}?
if field.Embed {?
g.Printf("%s%s %sn", field.fieldInfo.TypeName(), postfix, tagString)?
} else {?
g.Printf("%s %s%s %sn", field.Name, field.fieldInfo.TypeName(), postfix, tagString)?
}?
}?
g.Printf("}nn")?
?
g.Printf("type %[1]sJsonList []*%[1]sJsonnn", st.Name())?
?
// generate property builder?
g.Printf("type %[1]sPropertyEncoder func(src *%[1]s, dest *%[1]sJson) errornn", st.Name())?
g.Printf("type %[1]sPropertyDecoder func(src *%[1]sJson, dest *%[1]s) errornn", st.Name())?
?
// generate property info?
g.Printf(`?
type %[1]sPropertyInfo struct {?
name string?
Encoder %[1]sPropertyEncoder?
Decoder %[1]sPropertyDecoder?
}?
?
`, st.Name())?
?
// generate json builder?
∣介勻仁曰500俴適仁

犯市今
? genbase
? 介勻仁曰580俴仁日中
? jwg
? 介勻仁曰850俴仁日中
? 汜傖摽戊奈玉掂氏匹井日掂戶壬燴賤月
? ＃氏元扎卅中井卅嗣煦

Tips
? 鎚戶煋心struct反𤚗
? 汜傖允屯五戊奈玉互升氏升氏恚螝卞＃
? ?eld及倰互struct分午羯咡
? AST分仃匹反倰及��卅ロ�互卅中
? 汜傖戊奈玉卅中午戊件由奶伙籵日氏
? Printf及 %[1]s �楊穴斥晞瞳

I ? Pull Request
? 方曰Go日仄中𤩸五源匹五月方ㄐ
? 方曰�薹及謎中灍蚾互丐月方ㄐ
? Template妏尹方ㄐ
? text/template 反𠸎卞⻌日卅井勻凶＃
? 卅氏井卅中匹允井友ˋ
github.com/favclip

We are hiring!
? 嶱逃ㄩ氾伊申陳゜
? jwg, genbase 坻惇悊ㄐ
? http://www.favclip.com/
? appengine/go嶱逃氪羯揋躁摩笢ㄐ

疶�
? 仿奶皮仿伉及伉申斥亦件ˋ
? jwg 準誑𡥼卅劐載仄化中中及井仄日
? embed仄凶struct及丟末永玉網太贖
? 俋�及struct互receiver卞卅勻化幻仄
? Generics郗仄中𠸎厥切互眚尹日木卅中

躑曰?
? string及slice龰月午[]byte卅及支戶化?
? 1恅趼=1田奶玄穴件互釬月仿奶皮仿伉
? 婬䔝腔卅由永弗奈斥統桽偝仄化?
? 1由永弗奈斥互蕣癹卅仁匹井仁卅月＃
? err != nil 黱隙支月及分月中?

端端舝

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