Swift metatype (Type, self) -

i trying understand : "self, dynamictype, type". have code :

class someclass {}  let cls : someclass.type = someclass.self let cls2 : someclass = someclass() 

are cls , cls2 same thing ?

can give detail differences ?

no, cls , cls2 different things. easiest way understand difference extend example this:

class someclass {     class func doit() {         print("i'm class method. belong type.")     }      func doitonlyifinstanceofthistype() {         print("i'm instance method. belong type instance.")     } } 

and let's take cls:

let cls : someclass.type = someclass.self cls.doit() 

that print i'm class method. belong type.. cannot invoke this:

cls.doitonlyifinstanceofthistype() // causes compilation error, pro tip: can use method func property, i'll add explanation later 

let's take cls2. visible method of doitonlyifinstanceofthistype because it's instance method (of type).

let cls2 : someclass = someclass() cls2.doitonlyifinstanceofthistype() 

so difference between them cls type , cls2 instance of type.

a little bit more knowledge why someclass.self , someclass()?

the type of class exists in memory (it has example own methods), singleton representing type (not instance of type - that's different). if call self on type someclass.self singleton instance representing someclass type.

someclass() invokes init() method of someclass, constructor creates instance of someclass.

pro tip

you can manipulate type instance function (like closures/blocks in objc). it's generated class method. must pass instance of type take method argument, this:

let myfunc :()->() = cls.doitonlyifinstanceofthistype(cls2) myfunc()