1 files changed, 59 insertions, 11 deletions

diff --git a/src/data/thing.js b/src/data/thing.js
index 78ad3642..0a6e3be4 100644
--- a/src/data/thing.js
+++ b/src/data/thing.js
@@ -10,14 +10,27 @@ export default class Thing extends CacheableObject {
   static referenceType = Symbol.for('Thing.referenceType');
   static friendlyName = Symbol.for('Thing.friendlyName');
 
+  static wikiData = Symbol.for('Thing.wikiData');
+  static oneInstancePerWiki = Symbol.for('Thing.oneThingPerWiki');
+  static constitutibleProperties = Symbol.for('Thing.constitutibleProperties');
+
   static getPropertyDescriptors = Symbol.for('Thing.getPropertyDescriptors');
   static getSerializeDescriptors = Symbol.for('Thing.getSerializeDescriptors');
 
   static findSpecs = Symbol.for('Thing.findSpecs');
   static findThisThingOnly = Symbol.for('Thing.findThisThingOnly');
 
+  static reverseSpecs = Symbol.for('Thing.reverseSpecs');
+
   static yamlDocumentSpec = Symbol.for('Thing.yamlDocumentSpec');
-  static getYamlLoadingSpec = Symbol.for('Thing.getYamlLoadingSpec');
+
+  static yamlSourceFilename = Symbol.for('Thing.yamlSourceFilename');
+  static yamlSourceDocument = Symbol.for('Thing.yamlSourceDocument');
+  static yamlSourceDocumentPlacement = Symbol.for('Thing.yamlSourceDocumentPlacement');
+
+  [Symbol.for('Thing.yamlSourceFilename')] = null;
+  [Symbol.for('Thing.yamlSourceDocument')] = null;
+  [Symbol.for('Thing.yamlSourceDocumentPlacement')] = null;
 
   static isThingConstructor = Symbol.for('Thing.isThingConstructor');
   static isThing = Symbol.for('Thing.isThing');
@@ -26,14 +39,15 @@ export default class Thing extends CacheableObject {
   // Symbol.for('Thing.isThingConstructor') in constructor
   static [Symbol.for('Thing.isThingConstructor')] = NaN;
 
-  static [CacheableObject.propertyDescriptors] = {
+  constructor() {
+    super({seal: false});
+
     // To detect:
     // Object.hasOwn(object, Symbol.for('Thing.isThing'))
-    [Symbol.for('Thing.isThing')]: {
-      flags: {expose: true},
-      expose: {compute: () => NaN},
-    },
-  };
+    this[Symbol.for('Thing.isThing')] = NaN;
+
+    Object.seal(this);
+  }
 
   static [Symbol.for('Thing.selectAll')] = _wikiData => [];
 
@@ -49,7 +63,7 @@ export default class Thing extends CacheableObject {
       if (this.name) {
         name = colors.green(`"${this.name}"`);
       }
-    } catch (error) {
+    } catch {
       name = colors.yellow(`couldn't get name`);
     }
 
@@ -58,7 +72,7 @@ export default class Thing extends CacheableObject {
       if (this.directory) {
         reference = colors.blue(Thing.getReference(this));
       }
-    } catch (error) {
+    } catch {
       reference = colors.yellow(`couldn't get reference`);
     }
 
@@ -67,13 +81,47 @@ export default class Thing extends CacheableObject {
       (reference ? ` (${reference})` : ''));
   }
 
+  static clone(source, {as = null} = {}) {
+    if (!(source instanceof this)) {
+      throw new TypeError(
+        `Passed thing is ${source.constructor.name}, ` +
+        `which is not a subclass of ${this.name}`);
+    }
+
+    if (as && !(as.prototype instanceof this)) {
+      throw new TypeError(
+        `Passed constructor is ${as.name}, ` +
+        `which is not a subclass of ${this.name}`);
+    }
+
+    let clone;
+
+    if (as) {
+      clone = Reflect.construct(as, []);
+    } else {
+      clone = Reflect.construct(source.constructor, []);
+    }
+
+    CacheableObject.copyUpdateValuesOnto(source, clone);
+
+    return clone;
+  }
+
   static getReference(thing) {
     if (!thing.constructor[Thing.referenceType]) {
-      throw TypeError(`Passed Thing is ${thing.constructor.name}, which provides no [Thing.referenceType]`);
+      throw TypeError(
+        `Passed Thing is ${thing.constructor.name}, ` +
+        `which provides no [Thing.referenceType]`);
     }
 
     if (!thing.directory) {
-      throw TypeError(`Passed ${thing.constructor.name} is missing its directory`);
+      if (thing.name) {
+        throw TypeError(
+          `Passed ${thing.constructor.name} (named ${inspect(thing.name)}) ` +
+          `is missing its directory`);
+      } else {
+        throw TypeError(`Passed ${thing.constructor.name} is missing its directory`);
+      }
     }
 
     return `${thing.constructor[Thing.referenceType]}:${thing.directory}`;