io.getquill.context.qzio.ImplicitSyntax.scala Maven / Gradle / Ivy

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package io.getquill.context.qzio

import zio.{IO, Tag, ZEnvironment, ZIO}

/**
 * Use to provide `run(myQuery)` calls with a context implicitly saving the need
 * to provide things multiple times. For example in JDBC:
 * {{{
 *   case class MyQueryService(ds: DataSource) {
 *     import Ctx._
 *     implicit val env = Implicit(Has(ds))
 *
 *     val joes = Ctx.run(query[Person].filter(p => p.name == "Joe")).implicitly
 *     val jills = Ctx.run(query[Person].filter(p => p.name == "Jill")).implicitly
 *     val alexes = Ctx.run(query[Person].filter(p => p.name == "Alex")).implicitly
 *   }
 * }}}
 * Normally you would have to do a separate `provide` for each clause:
 * {{{
 *   val joes = Ctx.run(query[Person].filter(p => p.name == "Joe")).provide(Has(ds))
 *   val jills = Ctx.run(query[Person].filter(p => p.name == "Jill")).provide(Has(ds))
 *   val alexes = Ctx.run(query[Person].filter(p => p.name == "Alex")).provide(Has(ds))
 * }}}
 *
 * For other contexts e.g. Cassandra the functionality is identical.
 *
 * {{{
 *   case class MyQueryService(cs: CassandraZioSession) {
 *     import Ctx._
 *     implicit val env = Implicit(cs)
 *
 *     def joes = Ctx.run { query[Person].filter(p => p.name == "Joe") }.implicitly
 *     def jills = Ctx.run { query[Person].filter(p => p.name == "Jill") }.implicitly
 *     def alexes = Ctx.run { query[Person].filter(p => p.name == "Alex") }.implicitly
 *   }
 * }}}
 */
object ImplicitSyntax {

  /**
   * A new type that indicates that the value `R` should be made available to
   * the environment implicitly.
   */
  final case class Implicit[R](env: R)

  implicit final class ImplicitSyntaxOps[R, E, A](private val self: ZIO[R, E, A]) extends AnyVal {
    def implicitly(implicit r: Implicit[R], tag: Tag[R]): IO[E, A] = self.provideEnvironment(ZEnvironment(r.env))
  }
}