Let a variable hold a list

A variable could only be a number, a text or a yes/no, so every set of values had
to be smuggled through a string - which is where Tetris got its unreadable
"03066326048763714" colours from. A list is now a value of its own, with an item
kind (number, text, yes/no, colour) that decides how the inspector reads the one
comma-separated line it is typed as, and eight nodes to work with: List, Fill,
Count, Item at, Set item, Sub list, Join lists, Index of.

Two traps came with it. An array is typeof 'object', so every place that told a
value from an entity had to learn the difference, or a list would have been
passed around as a game object. And a value was compared by identity in three
places - with lists that marks everything as an overridden property after each
reload, so those comparisons now compare contents.

There is no list of objects: a list is written to the project file and an object
is a live handle that no reload survives. A set of objects stays a list of names.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/core/graph/values.ts

@@ -1,4 +1,4 @@
-import type { PropertyBag, PropertyValue } from '../model/Properties';
+import { isList, type ListValue, type PropertyBag, type PropertyValue } from '../model/Properties';
 import type { EntityHandle } from './NodeContext';
 
 /** A value travelling along a data edge. Objects are live entity handles (play mode only). */
@@ -11,9 +11,24 @@ export function asNumber(value: Value | undefined): number {
     const n = Number(value);
     return Number.isFinite(n) ? n : 0;
   }
+  if (isList(value)) return value.length;
   return 0;
 }
 
+/** Anything that is not a list reads as a one-item list, so a lone value can feed a list input. */
+export function asList(value: Value | undefined): ListValue {
+  if (isList(value)) return value;
+  if (value === null || value === undefined) return [];
+  return typeof value === 'object' ? [value.name] : [value];
+}
+
+/** A value narrowed to what a list may hold: handles and nested lists have no stored form. */
+export function asListItem(value: Value | undefined): number | string | boolean {
+  if (typeof value === 'number' || typeof value === 'boolean' || typeof value === 'string') return value;
+  if (value === null || value === undefined) return 0;
+  return asString(value);
+}
+
 export function asBoolean(value: Value | undefined): boolean {
   if (typeof value === 'string') return value !== '' && value !== 'false' && value !== '0';
   return Boolean(value);
@@ -22,12 +37,14 @@ export function asBoolean(value: Value | undefined): boolean {
 /** Entities read as their name, so a handle can be logged or joined into text directly. */
 export function asString(value: Value | undefined): string {
   if (value === null || value === undefined) return '';
+  if (isList(value)) return value.join(', ');
   if (typeof value === 'object') return value.name;
   return String(value);
 }
 
 export function asEntity(value: Value | undefined): EntityHandle | null {
-  return value && typeof value === 'object' ? value : null;
+  if (!value || typeof value !== 'object' || isList(value)) return null;
+  return value;
 }
 
 /**
@@ -36,7 +53,8 @@ export function asEntity(value: Value | undefined): EntityHandle | null {
  */
 export function writeTyped(bag: PropertyBag, key: string, value: Value | undefined): void {
   const current = bag[key];
-  if (typeof current === 'number') bag[key] = asNumber(value);
+  if (isList(current)) bag[key] = asList(value);
+  else if (typeof current === 'number') bag[key] = asNumber(value);
   else if (typeof current === 'boolean') bag[key] = asBoolean(value);
   else bag[key] = asString(value);
 }