Add specialized getters for returning `Collection`s to themselves

sources/Data/Collections/Collection.uc

@@ -522,7 +522,35 @@ public final function Text GetTextBy(BaseText jsonPointerAsText)
 }
 
 /**
- *  Returns an `HashTable` value (stored in the caller `Collection` or
+ *  Returns a generic `Collection` value (stored in the caller `Collection` or
+ *  one of it's sub-collections) pointed by
+ *  [JSON pointer](https://tools.ietf.org/html/rfc6901).
+ *  See `GetItemBy()` for more information.
+ *
+ *  Referred value must be stored as `Collection`
+ *  (or one of it's sub-classes) for this method to work.
+ *
+ *  @param  jsonPointerAsText   Description of a path to the `Collection` value.
+ *  @return `Collection` value, stored at `jsonPointerAsText` or
+ *      `none` if it is missing or has a different type.
+ */
+public final function Collection GetCollectionBy(
+    BaseText jsonPointerAsText)
+{
+    local Collection    asCollection;
+    local AcediaObject  result;
+
+    result = GetItemBy(jsonPointerAsText);
+    asCollection = Collection(result);
+    if (asCollection != none) {
+        return asCollection;
+    }
+    _.memory.Free(result);
+    return none;
+}
+
+/**
+ *  Returns a `HashTable` value (stored in the caller `Collection` or
  *  one of it's sub-collections) pointed by
  *  [JSON pointer](https://tools.ietf.org/html/rfc6901).
  *  See `GetItemBy()` for more information.
@@ -904,7 +932,34 @@ public final function Text GetTextByJSON(JSONPointer jsonPointer)
 }
 
 /**
- *  Returns an `HashTable` value (stored in the caller `Collection` or
+ *  Returns a generic `Collection` value (stored in the caller `Collection` or
+ *  one of it's sub-collections) pointed by JSON pointer.
+ *  See `GetItemByJSON()` for more information.
+ *
+ *  Referred value must be stored as `Collection`
+ *  (or one of it's sub-classes) for this method to work.
+ *
+ *  @param  jsonPointer JSON path to the `Collection` value.
+ *  @return `Collection` value, stored at `jsonPointerAsText` or
+ *      `none` if it is missing or has a different type.
+ */
+public final function Collection GetCollectionByJSON(
+    JSONPointer jsonPointer)
+{
+    local AcediaObject  result;
+    local Collection    asCollection;
+
+    result = GetItemByJSON(jsonPointer);
+    asCollection = Collection(result);
+    if (asCollection != none) {
+        return asCollection;
+    }
+    _.memory.Free(result);
+    return none;
+}
+
+/**
+ *  Returns a `HashTable` value (stored in the caller `Collection` or
  *  one of it's sub-collections) pointed by JSON pointer.
  *  See `GetItemByJSON()` for more information.
  *