Create README.md

Author: 2rebi

README.md

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+# golang-default
+[![Build Status](https://img.shields.io/endpoint.svg?url=https%3A%2F%2Factions-badge.atrox.dev%2FRebirthLee%2Fgolang-default%2Fbadge%3Fref%3Dmaster&style=flat)](https://actions-badge.atrox.dev/RebirthLee/golang-default/goto?ref=master)
+[![GitHub release (latest by date)](https://img.shields.io/github/v/release/rebirthlee/golang-default)](https://github.com/RebirthLee/golang-default/releases)
+[![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/rebirthlee/golang-default)](https://golang.org/doc/go1.13)
+[![license](https://img.shields.io/badge/license-BEER--WARE-green)](/LICENSE.md)
+
+Initialize or New Struct with default value
+
+## Setup
+```
+go get github.com/rebirthlee/golang-default
+```
+
+## Support type
+- `int/8/16/32/64`, `uint/8/16/32/64`
+```go
+`def:"100"` 
+`def:"-100"` // support only signed integer
+// support hexadecimal, octal, binary
+`def:"0xff"` // hexadecimal
+`def:"0xFF"` // hexadecimal
+`def:"0o77"` // octal
+`def:"0b11001111"` // binary
+```
+- `float32/64`
+```go
+`def:"3.141592653589"`
+`def:"-3.141592"`
+```
+- `complex64/128`
+```go
+ // `def:"{real part},{imaginary part}"`
+`def:"3.14,-10"`
+`def:"-3.14,3"`
+```
+- Nested Struct
+```go
+type Parent struct {
+	Name string `def:"Parent Struct"`
+	OneChild Child `def:"dive"`
+	TwoChild Child `def:"dive"`
+}
+
+type Child struct {
+	Key string `def:"unknown"`
+	Number int `def:"-1"`
+}
+```
+
+- Pointer of type
+```go
+type Parent struct {
+	Name *string `def:"Parent Struct"`
+	OneChild *Child `def:"dive"`
+	TwoChild *Child `def:"dive"`
+}
+
+type Child struct {
+	Key *string `def:"unknown"`
+	Number *int `def:"-1"`
+}
+```
+
+- Array
+```go
+type Sample struct {
+	Arr [3]int `def:"dive,-1"` // [-1, -1, -1]
+}
+```
+
+- Slice
+```go
+type Sample struct {
+	// `def:"dive({length},{capacity(optional)}),{value}"`
+	Sli []int `def:"dive(5),-1"` // [-1, -1, -1, -1, -1]
+  
+	//cap(SliWithCap) == 7
+	SliWithCap []NestedSample `def:"dive(3,7),dive"` // [{nested struct},{nested struct},{nested struct}] 
+}
+
+type NestedSample struct {
+	Name string `def:"nested struct"`
+}
+```
+
+- Map
+```go
+type Sample struct {
+	DiveMap map[string]*Struct `def:"dive{\"john doe\":dive,\"some one\":dive,\"key\":dive}"`
+/*
+	{ 
+		"john doe": &{who?},
+		"some one": &{who?},
+		"key": &{who?}
+	}
+*/ 
+	StructKeyMap map[*Struct]bool `def:"dive{dive:true,dive:false,dive:true}"`
+/*
+	{ 
+		&{who?}: true,
+		&{who?}: false,
+		&{who?}: true
+	}
+*/
+	DiveNestedMap map[string]map[*Struct]bool `def:"dive{\"key1\":dive{dive:true,dive:false},\"key2\":dive{dive:false,dive:false}}"`
+/*
+	{ 
+		"key1": {
+			&{who?}: true,
+			&{who?}: false
+		},
+		"key2": {
+			&{who?}: false,
+			&{who?}: false
+		}
+	}
+*/
+}
+
+Struct struct {
+	Name string `def:"who?"`
+}
+```
+
+- Json
+```go
+type Sample struct {
+	Arr [3]int `def:"[1,2,3]"` // [1,2,3] 
+	Sli []string `def:"[\"slice 1\",\"slice 2\"]"` // [slice 1,slice 2]
+	Map map[string]interface{} `def:"{\"key1\":123,\"key2\":\"value\",\"nested map\":{\"key\":\"val\"}}"` 
+/*
+	{ 
+		"key1":123,
+		"key2":"value",
+		"nested map":{
+			"key":"val"
+		}
+	}
+*/
+
+	Nested NestedSample `def:"{\"displayName\":\"nested struct type\"}"` // {nested struct type}
+	PtrNested *NestedSample `def:"{\"displayName\":\"nested struct pointer type\"}"` // &{nested struct pointer type}
+}
+
+type NestedSample struct {
+	Name string `json:"displayName"`
+}
+```
+
+- Function
+
+[Example](/example/func/main.go)
+
+## Usage
+### Simple
+
+```go
+import (
+	"fmt"
+	"github.com/rebirthlee/golang-default"
+)
+
+type Person struct {
+	Age int `def:"20"`
+	Name string `def:"hellp"`
+}
+
+...
+var p Person
+if err := def.Init(&p); err != nil {
+	// error handle
+}
+fmt.Println(p) //out: {20 hellp}
+```
+
+### Init
+If you got error, the next field of struct will not be initialized.
+
+```go
+if err := def.Init(&p); err != nil {
+	// error handle
+}
+```
+
+### JustInit
+Even though it has an error, It will try to initialize all fields.
+And you can know that error field of struct.
+
+```go
+if err := def.JustInit(&p); err != nil {
+	justErr := err.(*def.ErrorJustInit)
+	fmt.Println(justErr.Error())
+	// error handle
+}
+```
+
+### MustInit
+It isn't return error. but it will be panic when you has an error.
+
+```go
+def.MustInit(&p) // hasn't return error.
+```
+
+### New
+If you got error, it will be return nil.
+
+```go
+i, err := def.New(Person{})
+if err != nil {
+	// error handle
+} else {
+  p := i.(*Person)
+  fmt.Println(p) //out: &{20 hellp}
+}
+```
+
+### JustNew
+Even though it has an error, It must return pointer of struct with error.
+
+```go
+i, err := def.JustNew(Person{})
+if err != nil {
+	justErr := err.(*def.ErrorJustInit)
+	fmt.Println(justErr.Error())
+	// error handle
+} 
+p := i.(*Person)
+fmt.Println(p) //out: &{20 hellp}
+```
+
+### MustNew
+It isn't return error. but it will be panic when you has an error.
+
+```go
+p := def.MustNew(Person{}).(*Person) // hasn't return error.
+fmt.Println(p) //out: &{20 hellp}
+```
+
+License
+---
+[`THE BEER-WARE LICENSE (Revision 42)`](http://en.wikipedia.org/wiki/Beerware)