Builder pattern

added example code
updated readme (code and usage example)

creational/builder.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+
+	"./builder"
+)
+
+func main() {
+
+	assembly := car.NewAssembly(&car.Car{}).Color(car.RedColor)
+
+	familyCar := assembly.Wheels(car.SteelWheels).TopSpeed(50 * car.MPH).Build()
+	familyCar.Drive()
+
+	fmt.Printf("%#v\n", familyCar)
+	fmt.Printf("%#s\n", familyCar)
+
+	sportsCar := assembly.Wheels(car.SportsWheels).TopSpeed(150 * car.MPH).Build()
+	sportsCar.Drive()
+
+	fmt.Printf("%#v\n", sportsCar)
+	fmt.Printf("%#s\n", sportsCar)
+
+}

creational/builder.md

@@ -13,49 +13,159 @@ however passing a struct to the builder method fills the code with boilerplate
 ```go
 package car
 
-type Speed float64
-
-const (
-    MPH Speed = 1
-    KPH       = 1.60934
+import (
+	"fmt"
+	"log"
+	"strings"
 )
 
-type Color string
+type (
+	// Color is string representation of Vihicle color
+	Color string
 
-const (
-    BlueColor  Color = "blue"
-    GreenColor       = "green"
-    RedColor         = "red"
+	// Wheels is int representation of Vihicle wheels number
+	Wheels string
+
+	// Speed is string representation of Vihicle top speed
+	// representation in miles per hour
+	Speed float64
 )
 
-type Wheels string
+// Used constants definition
 
+// Type Wheels enum
 const (
-    SportsWheels Wheels = "sports"
-    SteelWheels         = "steel"
+	SportsWheels Wheels = "sports"
+	SteelWheels         = "steel"
 )
 
-type Builder interface {
-    Color(Color) Builder
-    Wheels(Wheels) Builder
-    TopSpeed(Speed) Builder
-    Build() Interface
+// Type Color Enum
+const (
+	BlueColor  Color = "blue"
+	GreenColor       = "green"
+	RedColor         = "red"
+)
+
+// Speed constants for easy spead conversation
+const (
+	MPH Speed = 1
+	KPH       = 1.60934
+)
+
+type Car struct {
+	color  Color
+	wheels Wheels
+	speed  Speed
 }
 
-type Interface interface {
-    Drive() error
-    Stop() error
+// Assembly is Assembly line struct that
+// implement Builder interface
+type Assembly struct {
+	v *Car
+}
+
+type Builder interface {
+	Color(Color) Builder
+	Wheels(Wheels) Builder
+	TopSpeed(Speed) Builder
+	Build() Vihicle
+}
+
+// Stoper for Stop implementation and intefae segregation
+type Stoper interface {
+	Stop()
+}
+
+// Driver for Drive implementation and interface segregation
+type Driver interface {
+	Drive()
+}
+
+// Vihicle interface to clarify what is vihicle:
+// - is it drives and if its stops its vihicle
+type Vihicle interface {
+	Stoper
+	Driver
+}
+
+// Vihicle interface implementation
+
+// Drive is driving the car
+func (c Car) Drive() {
+	fmt.Println("Car drives")
+}
+
+// Stop stops the car.
+func (c Car) Stop() {
+	fmt.Println("Car stops")
+}
+
+func (c Car) String() string {
+
+	var color string
+
+	if c.color != "" {
+		color = fmt.Sprintf("%s Car", strings.Title(string(c.color)))
+	} else {
+		color = "(Soon to be rusty) Car"
+	}
+
+	return fmt.Sprintf("%s on %s wheels with top speed %.2f mph", color, c.wheels, c.speed)
+}
+
+// Builder interface implementation
+
+// NewAssembly to create new Assembly line instance
+func NewAssembly(vihicle *Car) *Assembly {
+	return &Assembly{v: vihicle}
+}
+
+// Color building color option of car in assembly line.
+func (a *Assembly) Color(color Color) *Assembly {
+	a.v.color = color
+	return a
+}
+
+// Speed building speed option of car in assembly line.
+func (a *Assembly) TopSpeed(speed Speed) *Assembly {
+	if speed <= 0.0 {
+		log.Fatal("Final Product wouldn't be able to implement Drive interface")
+	}
+
+	if speed > 276.0 {
+		log.Fatal("Mister Musk, stop doing that, Tesla 3 fastest in the space, but not in on the earth")
+	}
+
+	a.v.speed = speed
+	return a
+}
+
+// Wheels building wheels option of car in assembly line.
+func (a *Assembly) Wheels(wheels Wheels) *Assembly {
+	a.v.wheels = wheels
+	return a
+}
+
+// Build interface Implementation
+func (a Assembly) Build() Vihicle {
+	return a.v
 }
 ```
 
 ## Usage
 
 ```go
-assembly := car.NewBuilder().Paint(car.RedColor)
+assembly := car.NewAssembly(&car.Car{}).Color(car.RedColor)
 
-familyCar := assembly.Wheels(car.SportsWheels).TopSpeed(50 * car.MPH).Build()
+familyCar := assembly.Wheels(car.SteelWheels).TopSpeed(50 * car.MPH).Build()
 familyCar.Drive()
 
-sportsCar := assembly.Wheels(car.SteelWheels).TopSpeed(150 * car.MPH).Build()
+fmt.Printf("%#v\n", familyCar)
+fmt.Printf("%#s\n", familyCar)
+
+sportsCar := assembly.Wheels(car.SportsWheels).TopSpeed(150 * car.MPH).Build()
 sportsCar.Drive()
+
+fmt.Printf("%#v\n", sportsCar)
+fmt.Printf("%#s\n", sportsCar)
 ```

creational/builder/car.go

@@ -0,0 +1,141 @@
+package car
+
+import (
+	"fmt"
+	"log"
+	"strings"
+)
+
+const Version = 1
+
+type (
+	// Color is string representation of Vihicle color
+	Color string
+
+	// Wheels is int representation of Vihicle wheels number
+	Wheels string
+
+	// Speed is string representation of Vihicle top speed
+	// representation in miles per hour
+	Speed float64
+)
+
+// Used constants definition
+
+// Type WheelsType enum
+const (
+	SportsWheels Wheels = "sports"
+	SteelWheels         = "steel"
+)
+
+// Type Color Enum
+const (
+	BlueColor  Color = "blue"
+	GreenColor       = "green"
+	RedColor         = "red"
+)
+
+// Speed constants for easy spead conversation
+const (
+	MPH Speed = 1
+	KPH       = 1.60934
+)
+
+type Car struct {
+	color  Color
+	wheels Wheels
+	speed  Speed
+}
+
+// Assembly is Assembly line struct that
+// implement Builder interface
+type Assembly struct {
+	v *Car
+}
+
+type Builder interface {
+	Color(Color) Builder
+	Wheels(Wheels) Builder
+	TopSpeed(Speed) Builder
+	Build() Vihicle
+}
+
+// Stoper for Stop implementation and intefae segregation
+type Stoper interface {
+	Stop()
+}
+
+// Driver for Drive implementation and interface segregation
+type Driver interface {
+	Drive()
+}
+
+// Vihicle interface to clarify what is vihicle:
+// - is it drives and if its stops its vihicle
+type Vihicle interface {
+	Stoper
+	Driver
+}
+
+// Vihicle interface implementation
+
+// Drive is driving the car
+func (c Car) Drive() {
+	fmt.Println("Car drives")
+}
+
+// Stop stops the car.
+func (c Car) Stop() {
+	fmt.Println("Car stops")
+}
+
+func (c Car) String() string {
+
+	var color string
+
+	if c.color != "" {
+		color = fmt.Sprintf("%s Car", strings.Title(string(c.color)))
+	} else {
+		color = "(Soon to be rusty) Car"
+	}
+
+	return fmt.Sprintf("%s on %s wheels with top speed %.2f mph", color, c.wheels, c.speed)
+}
+
+// Builder interface implementation
+
+// NewAssembly to create new Assembly line instance
+func NewAssembly(vihicle *Car) *Assembly {
+	return &Assembly{v: vihicle}
+}
+
+// Color building color option of car in assembly line.
+func (a *Assembly) Color(color Color) *Assembly {
+	a.v.color = color
+	return a
+}
+
+// Speed building speed option of car in assembly line.
+func (a *Assembly) TopSpeed(speed Speed) *Assembly {
+	if speed <= 0.0 {
+		log.Fatal("Final Product wouldn't be able to implement Drive interface")
+	}
+
+	if speed > 276.0 {
+		log.Fatal("Mister Musk, stop doing that, Tesla 3 fastest in the space, but not in on the earth")
+	}
+
+	a.v.speed = speed
+	return a
+}
+
+// Wheels building wheels option of car in assembly line.
+func (a *Assembly) Wheels(wheels Wheels) *Assembly {
+	a.v.wheels = wheels
+	return a
+}
+
+// Build interface Implementation
+func (a Assembly) Build() Vihicle {
+	return a.v
+}