simplify 'enum'

tests/enum.js

@@ -0,0 +1,46 @@
+import { makeTypeConstructor } from "../lib/meta/type_constructor.js";
+import { Char, Double, Unit } from "../lib/primitives/primitive_types.js";
+import { unit } from "../lib/primitives/unit.js";
+import { makeModuleEnum } from "../lib/structures/enum.types.js";
+import { newProduct } from "../lib/structures/product.js";
+import { lsType } from "../lib/structures/type_constructors.types.js";
+
+import assert from "node:assert";
+
+const variants = [
+  newProduct("fever")(_ => Double),
+  newProduct("confused")(_ => Unit),
+  newProduct("other")(_ => lsType(_ => Char)),
+];
+
+const symbolSymptom = "Symptom__c0442736bb6f11ae99a51b14e4db44b4";
+
+const Symptom = makeTypeConstructor(symbolSymptom)(0);
+
+const [
+  // constructors
+  [, {i: newFever}],
+  [, {i: newConfused}],
+  [, {i: newOther}],
+
+  // match function
+  [, {i: matchSymptom}],
+] = makeModuleEnum(Symptom)(variants);
+
+const fever = newFever(38.5);
+const confused = newConfused(unit);
+const other = newOther("sweating");
+
+console.log("observe the encoding of different variant instances:");
+console.log(" ", fever);
+console.log(" ", confused);
+console.log(" ", other);
+
+const description = symptom => matchSymptom(symptom)
+  (fever => `Fever (${fever} degrees)`)
+  (_confused => `Confused`)
+  (other => `Other: ${other}`);
+
+assert.strictEqual("Fever (38.5 degrees)", description(fever));
+assert.strictEqual("Confused"            , description(confused));
+assert.strictEqual("Other: sweating"     , description(other));