Initial commit

experiments/os1.mjs

@@ -0,0 +1,121 @@
+// Note: Only handled objects and primitives are allowed to be set/pushed/mapped
+
+import { inspect } from 'node:util';
+
+class Not_Storable_Error extends Error {
+	constructor({ storage, value, prop, id }) {
+		const type = value === null ? 'null' : typeof value;
+		const location = prop ? `property "${prop}" of record #${id}` : `record #${id}`;
+		super(`Cannot store value of type "${type}" in ${location}: ${inspect(value)}`);
+		this.name = 'Not_Storable_Error';
+		this.storage = storage;
+		this.value = value;
+	}
+}
+
+class Not_Mutable_Error extends Error {
+	constructor({ storage, value, prop, id }) {
+		const type = value === null ? 'null' : typeof value;
+		const location = prop ? `property "${prop}" of record #${id}` : `record #${id}`;
+		super(`Cannot set ${location}: record is immutable (tried to store value of type "${type}": ${inspect(value)})`);
+		this.name = 'Not_Mutable_Error';
+		this.storage = storage;
+		this.value = value;
+	}
+}
+
+
+function load_descriptor({ type, value }, { storage, mutable }) {
+	if (type === 'primitive') {
+		return value;
+	} else {
+		throw new Error('not implemented');
+	}
+}
+
+const Record_Handler = {
+
+	get(target, prop, receiver) {
+		const { storage, id, mutable } = target;
+
+		const result_descriptor = storage.get_record_property(id, prop);
+		if (result_descriptor) {
+			return load_descriptor(result_descriptor, { storage, mutable });
+		} else {
+			return undefined;
+		}
+	},
+
+	set(target, prop, value) {
+		const { storage, id, mutable } = target;
+
+		if (!mutable) {
+			throw new Not_Mutable_Error({ storage, id, prop, value });
+		}
+
+		if (!storage.can_be_stored(value)) {
+			throw new Not_Storable_Error({ storage, id, prop, value });
+		}
+
+		storage.set_record_property(id, prop, value);
+		return true;
+	}
+
+};
+
+
+class Storage {
+	#pending_id = 1;
+	#records = new Map();
+
+	create_record(data=undefined, mutable=true) {
+		const id = this.acquire_new_id();
+		const property_bag = {};
+		const result = new Proxy({
+			storage: this,
+			id,
+			property_bag,
+			mutable,
+		}, Record_Handler);
+
+		this.#records.set(id, property_bag);
+
+		if (data !== undefined) {
+			Object.assign(result, data);
+		}
+
+		return result;
+
+	}
+
+	get_record_property(item_id, property) {
+		console.log("Should get record property", { item_id, property });
+		return { type: 'primitive', value: 'Hello' };
+	}
+
+	set_record_property(item_id, property, value) {
+		console.log("Should set record property", { item_id, property, value });
+	}
+
+	can_be_stored(value) {
+		if (typeof value === 'string') {
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	acquire_new_id() {
+		return this.#pending_id++;
+	}
+
+
+};
+
+const s1 = new Storage();
+
+
+const p1 = s1.create_record({stuff: 'hello'}, true);
+console.log(p1.blargh);
+
+//p1.stuff = ['hello', 'world'];