make sure true results for delete actually work, add more examples

libraries/entities/src/EntityEditFilters.cpp

@@ -125,7 +125,7 @@ bool EntityEditFilters::filter(glm::vec3& position, EntityItemProperties& proper
                 return false;
             }
 
-            if (result.isObject()){
+            if (result.isObject()) {
                 // make propertiesIn reflect the changes, for next filter...
                 propertiesIn.copyFromScriptValue(result, false);
 
@@ -134,6 +134,17 @@ bool EntityEditFilters::filter(glm::vec3& position, EntityItemProperties& proper
                 // Javascript objects are == only if they are the same object. To compare arbitrary values, we need to use JSON.
                 auto out = QJsonValue::fromVariant(result.toVariant());
                 wasChanged |= (in != out);
+            } else if (result.isBool()) {
+
+                // if the filter returned false, then it's authoritative
+                if (!result.toBool()) {
+                    return false;
+                }
+
+                // otherwise, assume it wants to pass all properties
+                propertiesOut = propertiesIn;
+                wasChanged = false;
+                
             } else {
                 return false;
             }

scripts/tutorials/entity_edit_filters/prevent-add-of-entities-named-bob-example.js

@@ -0,0 +1,26 @@
+//
+// prevent-add-of-entities-named-bob-example.js
+// 
+//
+// Created by Brad Hefta-Gaub to use Entities on Jan. 25, 2018
+// Copyright 2018 High Fidelity, Inc.
+//
+// This sample entity edit filter script will get all edits, adds, physcis, and deletes, but will only block
+// deletes, and will pass through all others.
+//
+// Distributed under the Apache License, Version 2.0.
+// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+function filter(properties, type) {
+    if (properties.name == "bob") {
+        return false;
+    }
+    return properties;
+}
+
+filter.wantsToFilterAdd = true;  // do run on add
+filter.wantsToFilterEdit = false;  // do not run on edit
+filter.wantsToFilterPhysics = false;  // do not run on physics
+filter.wantsToFilterDelete = false;  // do not run on delete
+filter;