Generically transforming a type in Scala -

is there way of transforming type in generic manner? have this:

class super {   type messagestype = product   type aggregatortype = product }  class sub1 {    override type messagestype = (class1, class2)    override type aggregatortype = (option[class1], option[class2]) }  class sub2 {    override type messagestype = (class1, class2, class3)    override type aggregatortype = (option[class1], option[class2], option[class3]) } 

the aggregatortype contain options of each of types in messagestype. i've been looking @ ways of declaring messagestype in sub , having corresponding aggregatortype generated automatically. while i'm using tuples, change hlists, case classes, or whatever. however, have limitation of using shapeless 1.2.4 (due transitive dependencies).

any ideas?

you use mapped type class shapeless this.

it little bit difficult compiler infer of types. used nested class, maybe else can come prettier solution.

import shapeless._ import shapeless.ops.hlist.{mapped, tupler}  class withmessage[message <: product] {   class super[     g <: hlist,     m <: hlist,     t <: product   ](implicit      gen: generic.aux[message, g],  // tuple generic (hlist) representation     map: mapped.aux[g, option, m], // elements of g hlist in option     tup: tupler.aux[m, t]          // hlist m tuple   ) {     type aggregator = t     // ...   } } 

which can used :

val stringintmsg = new withmessage[(string, int)] object si extends stringintmsg.super  val si: si.aggregator = (some("foo"), some(1))