Add "rdfs:label" to Brick relation options

This is a tricky one because "rdfs:label" cannot really be queried from the Brick ontology, so it is a special case that probably needs to get added manually. Furthermore, an entity really shouldn't have multiple labels, so the option to give an entity an "rdfs:label"
 should only appear if it doesn't have one already. The way I did it meant I had to manually reset the Enum type in Blender because it was the active one selection and made the Enum blank since it got removed  now that the entity has a "rdfs:label." One possible alternative solution is to allow multiple labels, but in the query to import bricks in the UI list only select one label somehow.

src/blenderbim/blenderbim/bim/module/brick/prop.py

@@ -55,7 +55,13 @@ def get_brick_roots(self, context):
     return [(root, root, "") for root in BrickStore.root_classes]
 
 
-def get_brick_relations(self, context): # this will be queried from graph
+def get_brick_relations(self, context):
+    def is_label(relation):
+        return relation["predicate_name"] == "label"
+    if not list(filter(is_label, BrickschemaData.data["active_relations"])):
+        new_relations = BrickStore.relationships.copy()
+        new_relations.append(("http://www.w3.org/2000/01/rdf-schema#label", "label", ""))
+        return new_relations
     return BrickStore.relationships
 
 

src/blenderbim/blenderbim/bim/module/brick/ui.py

@@ -122,8 +122,9 @@ class BIM_PT_brickschema(Panel):
                 col.alignment = "RIGHT"
                 row.prop(data=self.props, property="split_screen_toggled", text="", icon="WINDOW")
 
-                row = self.layout.row(align=True)
-                prop_with_search(row, self.props, "new_brick_relation_namespace", text="")
+                if not self.props.new_brick_relation_type == "http://www.w3.org/2000/01/rdf-schema#label":
+                    row = self.layout.row(align=True)
+                    prop_with_search(row, self.props, "new_brick_relation_namespace", text="")
 
                 row = self.layout.row(align=True)
                 prop_with_search(row, self.props, "new_brick_relation_type", text="")

src/blenderbim/blenderbim/tool/brick.py

@@ -101,6 +101,12 @@ class Brick(blenderbim.core.tool.Brick):
 
     @classmethod
     def add_relation(cls, brick_uri, predicate, namespace, object):
+        if predicate == "http://www.w3.org/2000/01/rdf-schema#label":
+            with BrickStore.new_changeset() as cs:
+                cs.add((URIRef(brick_uri), URIRef(predicate), Literal(object)))
+            bpy.context.scene.BIMBrickProperties.new_brick_relation_type = BrickStore.relationships[0][0]
+            bpy.context.scene.BIMBrickProperties.add_relation_failed = False
+            return
         object_uri = namespace + object
         query = BrickStore.graph.query(
             "ASK { <{object_uri}> ?predicate ?object . }".replace(