From f074ae2978297b3a4e4d258ede257b538c4c8fe1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Fri, 22 May 2026 00:32:14 +0200
Subject: [PATCH] Refactor

---
 packages/effect-lens/src/Lens.ts | 109 +++++++++++++++++--------------
 1 file changed, 59 insertions(+), 50 deletions(-)

diff --git a/packages/effect-lens/src/Lens.ts b/packages/effect-lens/src/Lens.ts
index 52035ee..3a7359d 100644
--- a/packages/effect-lens/src/Lens.ts
+++ b/packages/effect-lens/src/Lens.ts
@@ -28,44 +28,63 @@ extends Subscribable.Subscribable<A, ER, RR> {
 export const isLens = (u: unknown): u is Lens<unknown, unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, LensTypeId)
 
 
+export const LensStepTypeId: unique symbol = Symbol.for("@effect-fc/Lens/LensStep")
+export type LensStepTypeId = typeof LensTypeId
 
-
-
-export const LensWithInternalsTypeId: unique symbol = Symbol.for("@effect-fc/Lens/LensWithInternals")
-export type LensWithInternalsTypeId = typeof LensWithInternalsTypeId
-
-export interface LensWithInternals<in out A, in out ER = never, in out EW = never, in out RR = never, in out RW = never>
-extends Lens<A, ER, EW, RR, RW> {
-    readonly [LensWithInternalsTypeId]: LensWithInternalsTypeId
-
-    readonly update: (a: A) => Effect.Effect<void, EW, RW>
-    readonly withLock: <A1, E1, R1>(self: Effect.Effect<A1, E1, R1>) => Effect.Effect<A1, EW | E1, RW | R1>
+export interface LensStep<in out A, in out B, in out ER = never, in out EW = never, in out RR = never, in out RW = never> {
+    readonly [LensStepTypeId]: LensStepTypeId
+    readonly transform: (parent: B) => Effect.Effect<A, ER, RR>
+    readonly update: (next: A, parent: B) => Effect.Effect<B, EW, RW>
 }
 
-export const isLensWithInternals = (u: unknown): u is LensWithInternals<unknown, unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, LensWithInternalsTypeId)
+export const isLensStep = (u: unknown): u is LensStep<unknown, unknown, unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, LensStepTypeId)
 
-export const asLensWithInternals = <A, ER, EW, RR, RW>(
-    lens: Lens<A, ER, EW, RR, RW>
-): LensWithInternals<A, ER, EW, RR, RW> => {
-    if (!isLensWithInternals(lens))
-        throw new Error("Not a 'LensWithInternals'.")
-    return lens as LensWithInternals<A, ER, EW, RR, RW>
-}
 
+// export const LensWithInternalsTypeId: unique symbol = Symbol.for("@effect-fc/Lens/LensWithInternals")
+// export type LensWithInternalsTypeId = typeof LensWithInternalsTypeId
+
+// export interface LensWithInternals<in out A, in out ER = never, in out EW = never, in out RR = never, in out RW = never>
+// extends Lens<A, ER, EW, RR, RW> {
+//     readonly [LensWithInternalsTypeId]: LensWithInternalsTypeId
+
+//     readonly update: (a: A) => Effect.Effect<void, EW, RW>
+//     readonly withLock: <A1, E1, R1>(self: Effect.Effect<A1, E1, R1>) => Effect.Effect<A1, EW | E1, RW | R1>
+// }
+
+// export const isLensWithInternals = (u: unknown): u is LensWithInternals<unknown, unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, LensWithInternalsTypeId)
+
+// export const asLensWithInternals = <A, ER, EW, RR, RW>(
+//     lens: Lens<A, ER, EW, RR, RW>
+// ): LensWithInternals<A, ER, EW, RR, RW> => {
+//     if (!isLensWithInternals(lens))
+//         throw new Error("Not a 'LensWithInternals'.")
+//     return lens as LensWithInternals<A, ER, EW, RR, RW>
+// }
+
+
+export const LensImplTypeId: unique symbol = Symbol.for("@effect-fc/Lens/LensImpl")
+export type LensImplTypeId = typeof LensImplTypeId
 
 export abstract class LensImpl<in out A, in out ER = never, in out EW = never, in out RR = never, in out RW = never>
-extends Pipeable.Class() {
+extends Pipeable.Class() implements Lens<A, ER, EW, RR, RW> {
     readonly [Readable.TypeId]: Readable.TypeId = Readable.TypeId
     readonly [Subscribable.TypeId]: Subscribable.TypeId = Subscribable.TypeId
     readonly [LensTypeId]: LensTypeId = LensTypeId
-    readonly [LensWithInternalsTypeId]: LensWithInternalsTypeId = LensWithInternalsTypeId
+    readonly [LensImplTypeId]: LensImplTypeId = LensImplTypeId
 
     abstract readonly get: Effect.Effect<A, ER, RR>
     abstract readonly changes: Stream.Stream<A, ER, RR>
-    abstract readonly update: (a: A) => Effect.Effect<void, EW, RW>
+    abstract readonly commit: (a: A) => Effect.Effect<void, EW, RW>
     abstract readonly withLock: <A1, E1, R1>(self: Effect.Effect<A1, E1, R1>) => Effect.Effect<A1, EW | E1, RW | R1>
 
-    modifyEffect = modifyEffect
+    modifyEffect<B, E1 = never, R1 = never>(
+        f: (a: A) => Effect.Effect<readonly [B, A], E1, R1>,
+    ): Effect.Effect<B, ER | EW | E1, RR | RW | R1> {
+        return this.withLock(Effect.flatMap(
+            this.get,
+            a => Effect.flatMap(f(a), ([b, next]) => Effect.as(this.commit(next), b),
+        )))
+    }
 }
 
 // export declare namespace LensImpl {
@@ -103,16 +122,6 @@ extends Pipeable.Class() {
 //     modifyEffect = modifyEffect
 // }
 
-function modifyEffect<A, B, ER = never, EW = never, E1 = never, RR = never, RW = never, R1 = never>(
-    this: LensWithInternals<A, ER, EW, RR, RW>,
-    f: (a: A) => Effect.Effect<readonly [B, A], E1, R1>,
-): Effect.Effect<B, ER | EW | E1, RR | RW | R1> {
-    return this.withLock(Effect.flatMap(
-        this.get,
-        a => Effect.flatMap(f(a), ([b, next]) => Effect.as(this.update(next), b),
-    )))
-}
-
 /**
  * Creates a `Lens` by supplying how to read the current value, observe changes, and apply transformations.
  */
@@ -121,26 +130,26 @@ export const make = <A, ER, EW, RR, RW>(
 ): Lens<A, ER, EW, RR, RW> => new LensImpl(source)
 
 
-export class LensLazyImpl<in out A, in out ER = never, in out EW = never, in out RR = never, in out RW = never>
-extends Pipeable.Class() implements LensWithInternals<A, ER, EW, RR, RW> {
-    readonly [Readable.TypeId]: Readable.TypeId = Readable.TypeId
-    readonly [Subscribable.TypeId]: Subscribable.TypeId = Subscribable.TypeId
-    readonly [LensTypeId]: LensTypeId = LensTypeId
-    readonly [LensWithInternalsTypeId]: LensWithInternalsTypeId = LensWithInternalsTypeId
+// export class LensLazyImpl<in out A, in out ER = never, in out EW = never, in out RR = never, in out RW = never>
+// extends Pipeable.Class() implements LensWithInternals<A, ER, EW, RR, RW> {
+//     readonly [Readable.TypeId]: Readable.TypeId = Readable.TypeId
+//     readonly [Subscribable.TypeId]: Subscribable.TypeId = Subscribable.TypeId
+//     readonly [LensTypeId]: LensTypeId = LensTypeId
+//     readonly [LensWithInternalsTypeId]: LensWithInternalsTypeId = LensWithInternalsTypeId
 
-    constructor(
-        readonly source: LensImpl.Source<A, ER, EW, RR, RW>
-    ) {
-        super()
-    }
+//     constructor(
+//         readonly source: LensImpl.Source<A, ER, EW, RR, RW>
+//     ) {
+//         super()
+//     }
 
-    get get() { return this.source.get }
-    get changes() { return this.source.changes }
-    get update() { return this.source.update }
-    get withLock() { return this.source.withLock }
+//     get get() { return this.source.get }
+//     get changes() { return this.source.changes }
+//     get update() { return this.source.update }
+//     get withLock() { return this.source.withLock }
 
-    modifyEffect = modifyEffect
-}
+//     modifyEffect = modifyEffect
+// }
 
 /**
  * Creates a `Lens` by supplying how to read the current value, observe changes, and apply transformations.