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This code illustrates some things you can do with duck types that you can't with static types (unless you add in casting, see Casting Types).

Code Block

static1 as int  //type is fixed to be an integer
dynamic1 as duck //can be anything

static1 = 0
dynamic1 = 0
print static1+1 //-> 1
print dynamic1+1 //-> 1

#static1 = "Some string" //error, cannot castconvert string to int
dynamic1 = "Some string" //dynamic1 can be "any" type of thing

#print static1.ToUpper() //error, static1 is an int, not a string
print dynamic1.ToUpper() //-> SOME STRING

//You can convert a static type to a dynamic duck type:
dynamic2 as duck = static1
print dynamic2 //-> 0
dynamic2 = "Some string"
print dynamic2.ToUpper() //-> SOME STRING

//or convert a dynamic type to a static type
static2 as string = dynamic1
print static2.ToUpper()

#static3 as int = dynamic1 //error, cannot cast string to int
#print static3 + 2


A Practical Example: Automating Internet Explorer via COM Interop

Code Block

import System.Threading

def CreateInstance(progid):
   type = System.Type.GetTypeFromProgID(progid)
   return type()

ie as duck = CreateInstance("InternetExplorer.Application")
ie.Visible = true

Thread.Sleep(50ms) while ie.Busy

document = ie.Document
print "$(document.title) is $(document.fileSize) bytes long."