| #!/bin/bash | |
| ######################################################################################################################### | |
| # MIT License | |
| # | |
| # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, | |
| # INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. | |
| # IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, | |
| # WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| // Define the following traits and companion object | |
| // It's in Rapture Core (https://github.com/propensive/rapture-core) if you don't want to | |
| trait LowPriorityDefaultsTo { implicit def fallback[T, S]: DefaultsTo[T, S] = null } | |
| object DefaultsTo extends LowPriorityDefaultsTo { implicit def defaultDefaultsTo[T]: DefaultsTo[T, T] = null } | |
| trait DefaultsTo[T, S] | |
| // Then, assuming we want to specify a default for a type class like `Namer`, | |
| case class Namer[T](name: String) |
| miles@frege:~$ ./shapeless.sh | |
| Loading... | |
| Welcome to the Ammonite Repl 0.5.2 | |
| (Scala 2.11.7 Java 1.8.0_51) | |
| @ val l = 23 :: "foo" :: true :: HNil | |
| l: Int :: String :: Boolean :: HNil = ::(23, ::("foo", ::(true, HNil))) | |
| @ |
Here is a fast explanation on this study for Freek to improve compile-time:
In Freek, Higher-Kinded Coproduct was based on Shapeless HList/Coproduct representation like:
sealed trait CoproductK[A] extends Product with Serializable
sealed trait CNilK[A] extends CoproductK[A]| module type TERM = sig | |
| type t | |
| type tvar | |
| val var_opt : t -> tvar option | |
| val compare_var : tvar -> tvar -> int | |
| val same_functor : t -> t -> bool | |
| val args : t -> t list | |
| end | |
| module Make (Term : TERM) = struct |
