[the-art] quadratic, squarer and sqrter

TODO.md

@@ -1,5 +1,3 @@
-[the-art] quadratic, squarer and sqrter
-
 [the-art] 实现能够处理 interval 的 propagator
 [the-art] use a scheduler
 [the-art] `merge` as generic lattice operations

src/the-art/toys/quadratic.test.ts

@@ -0,0 +1,21 @@
+import assert from "node:assert"
+import test from "node:test"
+import { addContent } from "../cell/addContent.js"
+import { content } from "../cell/index.js"
+import { quadratic } from "./quadratic.js"
+
+test("quadratic", () => {
+  {
+    const [r, s] = quadratic()
+    addContent(r, 2)
+
+    assert.deepStrictEqual(content(s), 4)
+  }
+
+  {
+    const [r, s] = quadratic()
+    addContent(s, 4)
+
+    assert.deepStrictEqual(content(r), 2)
+  }
+})

src/the-art/toys/quadratic.ts

@@ -0,0 +1,10 @@
+import { definePrimitive } from "../propagator/definePrimitive.js"
+import { definePropagator } from "../propagator/definePropagator.js"
+
+export const squarer = definePrimitive(2, (x) => x * x)
+export const sqrter = definePrimitive(2, (x) => Math.sqrt(x))
+
+export const quadratic = definePropagator(2, (r, s) => {
+  squarer(r, s)
+  sqrter(s, r)
+})