| """ | |
| This file contains a POC dependency-injection framework based on Scala's ZIO library. The idea is that | |
| each dependency can have one or more "layer," which specifies how to construct that type of dependency | |
| from other dependencies. These layers can be added to an "environment," which can construct a value | |
| for any type that you query, so long as layers have been added for it and and its upstream dependencies. | |
| Toward the end of the file there's a simple example demonstrating how this framework can be used for | |
| configuring an application. | |
| """ | |
Daniel Ciocîrlan recently published a video showcasing a dependency-injection (DI) approach developed by Martin Odersky that uses Scala's implicit resolution to wire dependencies automatically. (See also his reddit post.)
The basic pattern for defining services in Odersky's approach is as follows:
class Service(using Provider[(Dep1, Dep2, Dep3)])
| //> using scala 3.3 | |
| import scala.util.{Failure, NotGiven, Success, Try, boundary} | |
| import boundary.{Label, break} | |
| import scala.annotation.targetName | |
| /** | |
| * Proof of concept implementation of a syntax similar to Kotlin and | |
| * typescript. Within the context provided by [[getEither]], you can call | |
| * `?` on any optional/failable type (currently supports [[Option]], |
| //> using scala 3.3.0 | |
| import scala.util.{Try, Success, Failure} | |
| import scala.reflect.Typeable | |
| import scala.util.NotGiven | |
| import scala.annotation.implicitNotFound | |
| type Opt[T] = Opt.Opt[T] | |
| object Opt: |
| sealed trait Bool | |
| object Bool: | |
| sealed trait True extends Bool | |
| sealed trait False extends Bool | |
| sealed trait Nat | |
| object Nat: | |
| sealed trait _0 extends Nat | |
| sealed trait Succ[N <: Nat] extends Nat |