F# Decorator Pattern

Decorator Pattern

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// Decorator Pattern
[<AbstractClassAttribute>]
type ComputerParts() =
    abstract member Description :unit -> unit

type Computer() =
    inherit ComputerParts()
    override O.Description() = printf "I'm a Computer with"

type CDROM( c :ComputerParts ) =
    inherit ComputerParts()
    override O.Description() = c.Description(); printf ", CDROM"

type Mouse( c :ComputerParts ) =
    inherit ComputerParts()
    override O.Description() = c.Description(); printf ", Mouse"

type Keyboard( c :ComputerParts ) =
    inherit ComputerParts()
    override O.Description() = c.Description(); printf ", Keyboard"

let mutable computer = Computer() :> ComputerParts
computer <- Mouse( computer )
computer <- CDROM( computer )
computer <- Keyboard( computer )

computer.Description()

Multiple items
type AbstractClassAttribute =
inherit Attribute
new : unit -> AbstractClassAttribute

Full name: Microsoft.FSharp.Core.AbstractClassAttribute

--------------------
new : unit -> AbstractClassAttribute

Multiple items
type ComputerParts =
new : unit -> ComputerParts
abstract member Description : unit -> unit

Full name: Script.ComputerParts

--------------------
new : unit -> ComputerParts

abstract member ComputerParts.Description : unit -> unit

Full name: Script.ComputerParts.Description

type unit = Unit

Full name: Microsoft.FSharp.Core.unit

Multiple items
type Computer =
  inherit ComputerParts
  new : unit -> Computer
  override Description : unit -> unit

Full name: Script.Computer

--------------------
new : unit -> Computer

val O : Computer

override Computer.Description : unit -> unit

Full name: Script.Computer.Description

val printf : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printf

Multiple items
type CDROM =
  inherit ComputerParts
  new : c:ComputerParts -> CDROM
  override Description : unit -> unit

Full name: Script.CDROM

--------------------
new : c:ComputerParts -> CDROM

val c : ComputerParts

val O : CDROM

override CDROM.Description : unit -> unit

Full name: Script.CDROM.Description

abstract member ComputerParts.Description : unit -> unit

Multiple items
type Mouse =
  inherit ComputerParts
  new : c:ComputerParts -> Mouse
  override Description : unit -> unit

Full name: Script.Mouse

--------------------
new : c:ComputerParts -> Mouse

val O : Mouse

override Mouse.Description : unit -> unit

Full name: Script.Mouse.Description

Multiple items
type Keyboard =
  inherit ComputerParts
  new : c:ComputerParts -> Keyboard
  override Description : unit -> unit

Full name: Script.Keyboard

--------------------
new : c:ComputerParts -> Keyboard

val O : Keyboard

override Keyboard.Description : unit -> unit

Full name: Script.Keyboard.Description

val mutable computer : ComputerParts

Full name: Script.computer

Raw view Test code New version

More information

Link:	http://fssnip.net/k5
Posted:	11 years ago
Author:	Evanescent Devil
Tags:	design patterns , decorator pattern