Added module for Machine

[SandroMaglione]

Type

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update

Description

Added Machine module with Atom adapter:

• Machine ("state chart")
• AtomMachine integration for effect-atom

The feature is exposed under effect/unstable/machine.

import { Machine } from "effect/unstable/machine"

class Cart extends Schema.TaggedClass<Cart>("Cart")("Cart", {
  orderId: Schema.String
}) {}

class Editing extends Schema.TaggedClass<Editing>("Editing")("Editing", {}) {}
class Reviewing extends Schema.TaggedClass<Reviewing>("Reviewing")("Reviewing", {}) {}

class Checkout extends Schema.TaggedClass<Checkout>("Checkout")("Checkout", {
  orderId: Schema.String
}) {}

class Payment extends Schema.TaggedClass<Payment>("Payment")("Payment", {
  status: Schema.Literals(["pending", "paid"])
}) {}

class Delivery extends Schema.TaggedClass<Delivery>("Delivery")("Delivery", {
  status: Schema.Literals(["label", "shipped"])
}) {}

class Review extends Schema.TaggedClass<Review>("Review")("Review", {}) {}

class Submit extends Schema.TaggedClass<Submit>("Submit")("Submit", {
  orderId: Schema.String
}) {}

const OrderStates = Machine.defineStates({
  cart: {
    schema: Cart,
    initial: "editing",
    states: {
      editing: Editing,
      reviewing: Reviewing
    }
  },
  checkout: {
    schema: Checkout,
    type: "parallel",
    states: {
      payment: Payment,
      delivery: Delivery
    }
  }
})

const orderMachine = Machine.make({
  id: "Order",
  states: OrderStates.states,
  events: [Review, Submit],
  initial: () =>
    OrderStates.initial.cart(
      new Cart({ orderId: "order-1" }),
      (cart) => cart.editing(new Editing({}))
    )
}).handle({
  cart: {
    states: {
      editing: {
        on: {
          Review: ({ target }) => target.local.reviewing(new Reviewing({}))
        }
      },
      reviewing: {
        on: {
          Submit: ({ event, target }) =>
            target.full.checkout(
              new Checkout({ orderId: event.orderId }),
              (checkout) =>
                checkout
                  .payment(new Payment({ status: "pending" }))
                  .delivery(new Delivery({ status: "label" }))
            )
        }
      }
    }
  }
})

Feel free to push back on any of the API decisions or to propose or ask for any change.

Related

Moved over from the effect-smol PR.

This work is inspired by xstate, and it builds on top of #1945.

[changeset-bot]

🦋 Changeset detected

Latest commit: 04966cf

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 27 packages

Name	Type
effect	Patch
@effect/opentelemetry	Patch
@effect/platform-browser	Patch
@effect/platform-bun	Patch
@effect/platform-node-shared	Patch
@effect/platform-node	Patch
@effect/vitest	Patch
@effect/ai-anthropic	Patch
@effect/ai-openai-compat	Patch
@effect/ai-openai	Patch
@effect/ai-openrouter	Patch
@effect/atom-react	Patch
@effect/atom-solid	Patch
@effect/atom-vue	Patch
@effect/sql-clickhouse	Patch
@effect/sql-d1	Patch
@effect/sql-libsql	Patch
@effect/sql-mssql	Patch
@effect/sql-mysql2	Patch
@effect/sql-pg	Patch
@effect/sql-pglite	Patch
@effect/sql-sqlite-bun	Patch
@effect/sql-sqlite-do	Patch
@effect/sql-sqlite-node	Patch
@effect/sql-sqlite-react-native	Patch
@effect/sql-sqlite-wasm	Patch
@effect/openapi-generator	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[tim-smart]

What does the cluster integration look like?