wip cons list

jsconfig.json

@@ -2,7 +2,7 @@
   "compilerOptions": {
     "module": "es2020",
     "target": "es6",
-    "lib": ["es2022", "dom"],
+    "lib": ["esnext", "dom"],
     "checkJs": true,
     "paths": {
       "/*": ["./*"]

src/algebra/fn.js

@@ -1,5 +1,5 @@
 import { curry } from '../curry.js'
-import { Free, Suspend, pure } from './free.js'
+import { Free, Suspend, suspend, pure } from './free.js'
 
 /** @import {InferredMorphism, Morphism, ChainConstructor} from './types.js' */
 
@@ -35,9 +35,9 @@ export const kleisliCompose = curry(
 /**
  * @template T
  * @param {T} x
- * @returns {Free<T>}
+ * @returns {Suspend<T>}
  */
-export const liftF = x => new Suspend(
+export const liftF = x => suspend(
   x,
   /** @type {InferredMorphism<T>} */(pure)
 )

src/algebra/free.js

@@ -1,11 +1,15 @@
 import { liftF } from './fn.js'
-import { Algebra, Comonad, EitherOf, Functor, Monad } from './index.js'
+import { Algebra, BaseSet, Comonad, Monad } from './index.js'
 
 /** @import { InferredMorphism, Morphism } from './types.js' */
 
-/** @template T */
-export class Suspend extends Algebra(Functor, Monad) {
-  #value
+/**
+ * @template T
+ * @extends BaseSet
+ * @mixes Monad
+ */
+export class Suspend extends Algebra(Monad) {
+  _value
   #fn
 
   /**
@@ -14,7 +18,7 @@ export class Suspend extends Algebra(Functor, Monad) {
    */
   constructor(value, fn) {
     super()
-    this.#value = value
+    this._value = value
     this.#fn = fn
   }
 
@@ -30,7 +34,7 @@ export class Suspend extends Algebra(Functor, Monad) {
    * @returns {Suspend<T>}
    */
   chain(f) {
-    return new Suspend(this.#value, x => this.#fn(x).chain(f))
+    return new Suspend(this._value, x => this.#fn(x).chain(f))
   }
 
   /**
@@ -39,7 +43,7 @@ export class Suspend extends Algebra(Functor, Monad) {
    * @returns {Suspend<T>}
    */
   map(g) {
-    return new Suspend(this.#value, x => this.#fn(x).map(g))
+    return new Suspend(this._value, x => this.#fn(x).map(g))
   }
 
   /**
@@ -51,19 +55,23 @@ export class Suspend extends Algebra(Functor, Monad) {
     return this.map(g)
   }
 
+  step() {
+    return this.#fn(this._value)
+  }
+
   run() {
-    return this.#fn(this.#value)
+    return this.step().run()
   }
 }
 
 /** @template T */
-export class Pure extends Algebra(Functor, Monad, Comonad) {
-  #value
+export class Pure extends Algebra(Monad, Comonad) {
+  _value
 
   /** @param {T} value */
   constructor(value) {
     super()
-    this.#value = value
+    this._value = value
   }
 
   /** @returns {this is Pure<T>} */
@@ -78,7 +86,7 @@ export class Pure extends Algebra(Functor, Monad, Comonad) {
    * @returns {Pure<U>}
    */
   chain(f) {
-    return f(this.#value)
+    return f(this._value)
   }
 
   /**
@@ -100,11 +108,15 @@ export class Pure extends Algebra(Functor, Monad, Comonad) {
   }
 
   extract() {
-    return this.#value
+    return this._value
+  }
+
+  step() {
+    return this._value
   }
 
   run() {
-    return this.#value
+    return this._value
   }
 }
 

src/algebra/index.js

@@ -214,14 +214,8 @@ class Interface {
   }
 }
 
-/** @template T*/
-class BaseSet {
-  _value
-
-  /** @param {T} value */
-  constructor(value) {
-    this._value = value
-  }
+/** @template T */
+export class BaseSet {
 }
 
 /**
@@ -250,13 +244,19 @@ export const apply = (methodName, f, obj) => {
   }
 }
 
+/**
+ * @param {Function} base
+ * @returns {(...algebras: Interface[]) => FunctionConstructor}
+ */
+export const AlgebraWithBase = base => (...algebras) => {
+  return mix(base).with(...algebras.map(x => x.intoWrapper()))
+}
+
 /**
  * @param {...Interface} algebras
  * @returns {FunctionConstructor}
  */
-export const Algebra = (...algebras) => {
-  return mix(BaseSet).with(...algebras.map(x => x.intoWrapper()))
-}
+export const Algebra = AlgebraWithBase(BaseSet)
 
 export const Setoid = new Interface('Setoid')
   .specifies('equals')
@@ -331,7 +331,7 @@ export const Chain = new Interface('Chain')
     Method.from('chain')
       .implementation(function(f) {
         return f(this._value)
-      }))
+      })
   )
 
 export const ChainRef = new Interface('ChainRec')

src/algebra/list.js

@@ -1,54 +1,110 @@
 import { liftF } from './fn.js'
-import { Free } from './free.js'
-import { Algebra, Foldable, Functor, Monad } from './index.js'
-import { none as None } from './option.js'
+import { Pure, Suspend } from './free.js'
+import { AlgebraWithBase, Comonad, Foldable } from './index.js'
 
-/** @template T */
-export class List extends Algebra(Functor, Monad, Foldable) {
-  /** @type {Free<T> | None<T>} */
-  _head
+/** @import { InferredMorphism } from './types.js' */
 
-  /** @type {List<T>} */
-  _tail
+const Nil = Symbol('Nil')
 
-  /**
-   * @param {T | None} [head]
-   * @param {List<T>} [tail=List]
-   */
-  constructor(head = None, tail = List.of(None)) {
-    super()
-    this._head = head
-    this._tail = tail
+/**
+ * @template T
+ * @extends {Pure<T>}
+ */
+class ListPure extends AlgebraWithBase(Pure)(Foldable) {
+  head() {
+    return this.head
+  }
+
+  tail() {
+    return Empty
   }
 
   /**
-   * @template T
-   * @param {T} value 
-   * @returns {List<T>}
+   * @template U
+   * @param {(acc: U, value: T) => U} f 
+   * @param {U} init 
+   * @returns {U}
    */
-  prepend(value) {
-    return new List(value, this)
-  }
-
-  /**
-   * @template T
-   * @param {T} value 
-   * @returns {List<T>}
-   */
-  static of(value) {
-    return new List(value)
-  }
-
-  /**
-   * @template T
-   * @param {Iterable<T>} iterable 
-   * @returns {List<T>}
-   */
-  static from(iterable) {
-    Array.from(iterable).reduceRight((list, value))
+  reduce(f, init) {
+    return f(init, this._value)
   }
 }
 
-const list = liftF(1)
-console.log(list.map(_ => 2).map(_ => 3).chain(x => x).run())
+
+/**
+ * @template T
+ * @extends {Suspend<T>}
+ */
+class ListSuspend extends AlgebraWithBase(Suspend)(Foldable, Comonad) {
+  /**
+   * @param {IteratorObject<T>} iter
+   */
+  constructor(iter) {
+    const next = iter.next()
+    const value = /** @type {T} */ (next.value)
+
+    const fn = /** @type {InferredMorphism<T>} */ (next.done ? List.empty : () => new ListSuspend(iter))
+    super(value, fn)
+  }
+
+  head() {
+    return this._value
+  }
+
+  tail() {
+    return this.step()
+  }
+
+  /**
+   * @template U
+   * @param {(acc: U, value: T) => U} f 
+   * @param {U} init 
+   * @returns {U}
+   */
+  reduce(f, init) {
+    const acc = f(init, this._value)
+    return this.tail().reduce(f, acc)
+  }
+
+  extract() {
+    return this.reduce((acc, value) => acc.concat(value), [])
+  }
+}
+
+/**
+ * @template T
+ * @type {ListPure<T> | ListSuspend<T>} List
+ */
+export class List {
+  /**
+   * @template {Iterable<T>} T
+   * @param {T} value 
+   * @returns {ListSuspend<T>}
+   */
+  static of(value) {
+    // @ts-ignore
+    return new ListSuspend(liftF(value))
+  }
+
+  /**
+   * @template T
+   * @param {Iterable<T>} iterator 
+   * @returns {ListSuspend<T>}
+   */
+  static from(iterator) {
+    return new ListSuspend(Iterator.from(iterator))
+  }
+
+  static empty() {
+    return Empty
+  }
+}
+
+const Empty = new ListPure(Nil)
+
+
+const a = Array.from({ length: 100 }).map((_, i) => i)
+
+const wawa = List.from(a)
+console.log(wawa.reduce((acc, value) => acc.concat(value), []))