Typelevel
DSL
present day
present time
Все знают,
что такое
DSL,
и зачем
они нужны
Specific
name = readLine("name")
age = readLine("age")
putLine(name)
putLine(age)Domain
Language
<Program>
<setVariable name="name">
<readLine prompt = "name"/>
</setVariable>
<setVariable name="age">
<readLine prompt= "age"/>
</setVariable>
<putLine title = "name">
<getVariable name= "name"/>
</putLine>
<putLine title = "age">
<getVariable name = "age"/>
</putLine>
</Program>- cmd: set
name: name
value:
cmd: readLine
promt: name
- cmd: set
name: age
value:
cmd: readLine
promt: age
- cmd: putLine
title: name
value:
- cmd: get
name: name
- cmd: putLine
title: age
value:
- cmd: get
name: age
Runtime
Errors
def program[F[_] : Console]: F[Unit] =
for {
name <- readLine("name")
age <- readLine("age")
_ <- putLine("name")(name)
_ <- putLine("age")(age)
} yield ()Free Algebras
Freer/Eff
Finally tagless
def program[~:>[_[_], _[_, _] : Console,
Env[_,_]]]: Initial ~:> Env =
('name := readLine("name")) >->
('age := readLine("age")) >->
do_(putLine("name") $ 'name) >->
do_(putLine("age") $ 'name) much free
so composable
Eff
kiselyov ftp wow
very tagless
import doge.implicits._
compilation time: 13 days
Все знают,
что такое
Типы,
и зачем
они нужны
case class User(
name: String,
age: Int
)Описывают
низкоуровневую структуру
def combineAll[A: Monoid](
xs: List[A]
): AНакладывают ограничения
Открывают избирательный
доступ к функционалу
trait PrependOrdered[
N <: Nat,
Len <: Nat,
V <: OrderedVec[L]]{
type Result <: OrderedVec[S[Len]]
def append(xs: V): Result
}Могут служить доказательтвами
implicit val intEncoder extends Encoder[Int]
implicit def listEncoder[A]
(implicit item: Encoder[A]): Encoder[List[A]]implicitly[Encoder[List[Int]]listEncoder(intEncoder)type Program =
('name := readLine["name"]) >>
('age := readLine["age"]) >>
(putLine["name"] $ 'name) >>
(putLine["age"] $ 'age) 
trait Program
case class ReadLine(name: String) extends Program
case class PutLine(name: String) extends Program
case class Cons(left: Program, right: Program) extends Programtrait Program
trait ReadLine[name <: String] extends Program
trait WriteLine[name <: String] extends Program
trait Cons[left <: Program, right <: Program] extends ProgramLAYER1: IMPLICITS
TRUE WAY
Text
SANE WAY
LAYER 2: MACROS
LAYER 3: EFFECTS
NO WAY
THIS ISN'T EVEN
MY FINAL FORM
Что нужно?
implicit def cons[
left,
right,
Input]
(implicit left: Interpret[left, Input])
(implicit right: Interpret[right, left.Output])
: Interpret[left >> right, Input]{type Output = right.Output}Multiple implicit parameter lists
(https://github.com/lampepfl/dotty/issues/1260)
Typelevel Functions
type def LiftRecord[R <: Record[F], G[_]] = R match {
case RNil[F] => RNil[G]
case RCons[F, K, V, Tail] =>
RCons[G, K, LiftValue[V, G], LiftRecord[G]]
}Что нужно?
Спасибо за внимание!
typelevel dsl
By Oleg Nizhnik
