Pool is subtype of Effect

.changeset/lemon-worms-return.md

@@ -0,0 +1,5 @@
+---
+"effect": minor
+---
+
+`Pool` is now a subtype of `Effect`, equivalent to `Pool.get`

packages/effect/dtslint/Unify.ts

@@ -7,6 +7,7 @@ import type * as FiberRef from "effect/FiberRef"
 import type * as ManagedRuntime from "effect/ManagedRuntime"
 import type * as Micro from "effect/Micro"
 import type * as Option from "effect/Option"
+import type * as Pool from "effect/Pool"
 import type * as Queue from "effect/Queue"
 import type * as RcRef from "effect/RcRef"
 import type * as Ref from "effect/Ref"
@@ -116,6 +117,13 @@ export type DequeueUnify = Unify.Unify<
   | Queue.Dequeue<1>
   | Queue.Dequeue<"a">
 >
+// $ExpectType Pool<1, 2> | Pool<"a", "b" | "c">
+export type PoolUnify = Unify.Unify<
+  | Pool.Pool<1, 2>
+  | Pool.Pool<"a", "b">
+  | Pool.Pool<"a", "c">
+>
+
 // $ExpectType ScopedRef<1> | ScopedRef<"a">
 export type ScopedRefUnify = Unify.Unify<
   | ScopedRef.ScopedRef<1>
@@ -130,7 +138,7 @@ export type ResourceUnify = Unify.Unify<
   | Resource.Resource<any, any>
 >
 
-// $ExpectType 0 | Option<string | number> | Ref<1> | Ref<"a"> | SynchronizedRef<1> | SynchronizedRef<"a"> | SubscriptionRef<1> | SubscriptionRef<"a"> | RcRef<"a", "b"> | Deferred<"a", "b"> | FiberRef<1> | FiberRef<"a"> | ManagedRuntime<"a", "b"> | Queue<1> | Queue<"a"> | Dequeue<"a" | 1> | ScopedRef<1> | ScopedRef<"a"> | Resource<"a", "b"> | RcRef<1, 0> | Deferred<1, 0> | Resource<1, 0> | Latch | ManagedRuntime<1, 0> | Fiber<"a" | 1, 0 | "b"> | RuntimeFiber<"a" | 1, 0 | "b"> | Either<"a" | 1, 0 | "b"> | Effect<"a" | 1, 0 | "b", "R" | "R1">
+// $ExpectType 0 | Option<string | number> | Ref<1> | Ref<"a"> | SynchronizedRef<1> | SynchronizedRef<"a"> | SubscriptionRef<1> | SubscriptionRef<"a"> | RcRef<"a", "b"> | Deferred<"a", "b"> | FiberRef<1> | FiberRef<"a"> | ManagedRuntime<"a", "b"> | Queue<1> | Queue<"a"> | Dequeue<"a" | 1> | Pool<1, 2> | Pool<"a", "b" | "c"> | ScopedRef<1> | ScopedRef<"a"> | Resource<"a", "b"> | RcRef<1, 0> | Deferred<1, 0> | Resource<1, 0> | Latch | ManagedRuntime<1, 0> | Fiber<"a" | 1, 0 | "b"> | RuntimeFiber<"a" | 1, 0 | "b"> | Either<"a" | 1, 0 | "b"> | Effect<"a" | 1, 0 | "b", "R" | "R1">
 export type AllUnify = Unify.Unify<
   | Either.Either<1, 0>
   | Either.Either<"a", "b">
@@ -158,6 +166,9 @@ export type AllUnify = Unify.Unify<
   | Queue.Queue<"a">
   | Queue.Dequeue<1>
   | Queue.Dequeue<"a">
+  | Pool.Pool<1, 2>
+  | Pool.Pool<"a", "b">
+  | Pool.Pool<"a", "c">
   | ScopedRef.ScopedRef<1>
   | ScopedRef.ScopedRef<"a">
   | Resource.Resource<1, 0>

packages/effect/src/Pool.ts

@@ -7,6 +7,7 @@ import * as internal from "./internal/pool.js"
 import type { Pipeable } from "./Pipeable.js"
 import type * as Scope from "./Scope.js"
 import type * as Types from "./Types.js"
+import type * as Unify from "./Unify.js"
 
 /**
  * @since 2.0.0
@@ -28,7 +29,7 @@ export type PoolTypeId = typeof PoolTypeId
  * @since 2.0.0
  * @category models
  */
-export interface Pool<in out A, out E = never> extends Pool.Variance<A, E>, Pipeable {
+export interface Pool<in out A, out E = never> extends Pool.Variance<A, E>, Effect.Effect<A, E, Scope.Scope>, Pipeable {
   /**
    * Retrieves an item from the pool in a scoped effect. Note that if
    * acquisition fails, then the returned effect will fail for that same reason.
@@ -42,6 +43,30 @@ export interface Pool<in out A, out E = never> extends Pool.Variance<A, E>, Pipe
    * than eagerly.
    */
   invalidate(item: A): Effect.Effect<void>
+
+  readonly [Unify.typeSymbol]?: unknown
+  readonly [Unify.unifySymbol]?: PoolUnify<this>
+  readonly [Unify.ignoreSymbol]?: PoolUnifyIgnore
+}
+
+/**
+ * @category models
+ * @since 3.9.0
+ */
+export interface PoolUnify<A extends { [Unify.typeSymbol]?: any }> extends Effect.EffectUnify<A> {
+  Pool?: () => Extract<A[Unify.typeSymbol], Pool<any, any>> extends Pool<infer A0, infer _E0> | infer _ ?
+    A0 extends any ? Extract<A[Unify.typeSymbol], Pool<A0, any>> extends Pool<A0, infer E1> ? Pool<A0, E1>
+      : never
+    : never :
+    never
+}
+
+/**
+ * @category models
+ * @since 3.9.0
+ */
+export interface PoolUnifyIgnore extends Effect.EffectUnifyIgnore {
+  Effect?: true
 }
 
 /**

packages/effect/src/internal/pool.ts

@@ -2,6 +2,7 @@ import type { Cause } from "effect/Cause"
 import * as Context from "../Context.js"
 import * as Duration from "../Duration.js"
 import type { Effect, Semaphore } from "../Effect.js"
+import * as Effectable from "../Effectable.js"
 import type { Exit } from "../Exit.js"
 import { dual, identity } from "../Function.js"
 import * as Iterable from "../Iterable.js"
@@ -122,7 +123,7 @@ interface Strategy<A, E> {
   readonly reclaim: (pool: PoolImpl<A, E>) => Effect<Option.Option<PoolItem<A, E>>>
 }
 
-class PoolImpl<A, E> implements Pool<A, E> {
+class PoolImpl<A, E> extends Effectable.Class<A, E, Scope> implements Pool<A, E> {
   readonly [PoolTypeId]: Pool.Variance<A, E>[PoolTypeId_]
 
   isShuttingDown = false
@@ -140,6 +141,7 @@ class PoolImpl<A, E> implements Pool<A, E> {
     readonly strategy: Strategy<A, E>,
     readonly targetUtilization: number
   ) {
+    super()
     this[PoolTypeId] = poolVariance
     this.semaphore = circular.unsafeMakeSemaphore(concurrency * maxSize)
   }
@@ -253,6 +255,10 @@ class PoolImpl<A, E> implements Pool<A, E> {
     )
   )
 
+  commit() {
+    return this.get
+  }
+
   readonly get: Effect<A, E, Scope> = core.flatMap(
     core.suspend(() => this.isShuttingDown ? core.interrupt : this.getPoolItem),
     (_) => _.exit

packages/effect/test/Pool.test.ts

@@ -423,4 +423,14 @@ describe("Pool", () => {
       expect(yield* Ref.get(allocations)).toBe(11)
       expect(yield* Ref.get(released)).toBe(11)
     }))
+
+  it.scoped("is subtype of Effect", () =>
+    Effect.gen(function*() {
+      const pool = yield* Pool.make({
+        acquire: Effect.succeed(1),
+        size: 1
+      })
+      const item = yield* pool
+      assert.strictEqual(item, 1)
+    }))
 })