1 files changed, 52 insertions, 4 deletions

diff --git a/src/data/thing.js b/src/data/thing.js
index 706e893d..66f73de5 100644
--- a/src/data/thing.js
+++ b/src/data/thing.js
@@ -14,20 +14,68 @@ export default class Thing extends CacheableObject {
   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');
+
+  // To detect:
+  // Symbol.for('Thing.isThingConstructor') in constructor
+  static [Symbol.for('Thing.isThingConstructor')] = NaN;
+
+  constructor() {
+    super({seal: false});
+
+    // To detect:
+    // Object.hasOwn(object, Symbol.for('Thing.isThing'))
+    this[Symbol.for('Thing.isThing')] = NaN;
+
+    Object.seal(this);
+  }
+
+  static [Symbol.for('Thing.selectAll')] = _wikiData => [];
+
   // Default custom inspect function, which may be overridden by Thing
   // subclasses. This will be used when displaying aggregate errors and other
   // command-line logging - it's the place to provide information useful in
   // identifying the Thing being presented.
   [inspect.custom]() {
-    const cname = this.constructor.name;
+    const constructorName = this.constructor.name;
+
+    let name;
+    try {
+      if (this.name) {
+        name = colors.green(`"${this.name}"`);
+      }
+    } catch (error) {
+      name = colors.yellow(`couldn't get name`);
+    }
+
+    let reference;
+    try {
+      if (this.directory) {
+        reference = colors.blue(Thing.getReference(this));
+      }
+    } catch (error) {
+      reference = colors.yellow(`couldn't get reference`);
+    }
 
     return (
-      (this.name ? `${cname} ${colors.green(`"${this.name}"`)}` : `${cname}`) +
-      (this.directory ? ` (${colors.blue(Thing.getReference(this))})` : '')
-    );
+      (name ? `${constructorName} ${name}` : `${constructorName}`) +
+      (reference ? ` (${reference})` : ''));
   }
 
   static getReference(thing) {