swift - Use Self as generic type -

self can used return type of method:

func dosomething() -> self {} 

is somehow possible use self generic type this?

func dosomething() -> wrapper<self> {} 

example

it nice if subclass christmaspresent , let have wrapped function returns wrappedpresent generic set whatever subclass was.

class christmaspresent {     func wrapped() -> wrappedpresent<self> {         return wrappedpresent(present: self)     } }  class wrappedpresent<t: christmaspresent> {     var present: t      init(present: t) {         self.present = present     } }  class toycar: christmaspresent {}  let wrappedtoycar = toycar().wrapped() // inferred be: wrappedpresent<toycar>  

the vexing paradox in swift this: "swift prefers methods, swift's functions more powerful." swift team knows that, , someday have powerful methods. today not day. there many things you'd express in methods cannot. want can done functions, however.

class christmaspresent {}  struct wrappedpresent<t: christmaspresent> {     let present: t }  func wrap<t:christmaspresent>(present: t) -> wrappedpresent<t> {     return wrappedpresent(present: present); }  class toycar: christmaspresent {}  let wrappedtoycar = wrap(toycar()) // inferred be: wrappedpresent<toycar> 

note if code did compile, might still quite surprised @ result. swift custom types not covariant, wrappedpresent<toycar> not subtype of wrappedpresent<christmaspresent>. if had array of wrapped presents, not put wrapped toycar in it. force using fixed (non-type-parameterized) wrappedpresent type anyway, making question moot. generics , classes not mix might imagine in swift.

if have practical example of problem you'd want solve this, recommend bringing on dev forums. swift team responsive.