ios - How to use extension methods as arguments in Swift? -

i implement dsl similar can builders in kotlin: http://kotlinlang.org/docs/reference/type-safe-builders.html

the idea use extension methods function arguments, can use methods class being extended within closure give argument. allowing inject methods , variables scope of closure.

it seems almost possible in swift, maybe missing something. following code works, right until try call head() within closure:

// class method available within closure class html {       func head() {           print("head")       }   }    // create type same signature extension method   typealias ext_method = html -> () -> ()    func html(op: ext_method) {       let html = html()       op(html)() // call extension method }    html {       head() // ! use of unresolved identifier 'head'   } 

have had luck doing similar, or have idea how possible?

i have no idea if looking for, but

html {     $0.head   } 

would compile , seems produce expected output.

the closure takes single parameter (here using shorthand parameter name $0) instance of html. returns instance method $0.head function of type () -> ().