scala - HList as parameter of method with simplified type signature -

suppose have container-marker

case class typedstring[t](value: string) 

where value represents id particular type t.

i have 2 classes

case class user(id: string) case class event(id: string) 

and have function stuff:

def func[l <: hlist](l: l)(...) {...} 

so can use

func[typedstring[user] :: typedstring[event] :: hnil](     typedstring[user]("user id") :: typedstring[event]("event id") :: hnil ) 

(it's important me keep type signature explicitly)

the question is: how change or extends func have shorter type signature (keeping marker types) like:

func[user :: event :: hnil](     typedstring[user]("user id") :: typedstring[event]("event id") :: hnil ) 

the shapeless.ops.hlist.mapped type class gives relation of 1 hlist l , hlist elements of l wrapped in type constructor.

because have 2 types, type l want specify , type (the elements of l wrapped in typedstring), need use same trick used in your previous question (then because didn't want supply arguments @ once, because want specify first type).

import shapeless._ import ops.hlist.mapped  def func[l <: hlist] = new partfunc[l]  class partfunc[l <: hlist] {   def apply[m <: hlist](m: m)(implicit mapped: mapped.aux[l, typedstring, m]): m = m } 

now can use func wanted :

func[user :: event :: hnil](     typedstring[user]("user id") :: typedstring[event]("event id") :: hnil ) // typedstring[user] :: typedstring[event] :: hnil = //     typedstring(user id) :: typedstring(event id) :: hnil