Add util module to IfcOpenShell, including element, geolocation, unit, and selector. See #829.

src/ifcopenshell-python/ifcopenshell/util/element.py

@@ -0,0 +1,35 @@
+def get_psets(element):
+    psets = {}
+    try:
+        if element.is_a('IfcTypeObject'):
+            if element.HasPropertySets:
+                for definition in element.HasPropertySets:
+                    psets[definition.Name] = get_properties(definition)
+        else:
+            for relationship in element.IsDefinedBy:
+                if relationship.is_a('IfcRelDefinesByProperties'):
+                    definition = relationship.RelatingPropertyDefinition
+                    psets[definition.Name] = get_properties(definition)
+    except Exception as e:
+        import traceback
+        print('failed to load properties: {}'.format(e))
+        traceback.print_exc()
+    return psets
+
+def get_properties(definition):
+    if definition is not None:
+        props = {}
+        if definition.is_a('IfcElementQuantity'):
+            for q in definition.Quantities:
+                if q.is_a('IfcPhysicalSimpleQuantity'):
+                    props[q.Name] = q[3]
+        elif definition.is_a('IfcPropertySet'):
+            for prop in definition.HasProperties:
+                if prop.is_a('IfcPropertySingleValue'):
+                    props[prop.Name] = prop.NominalValue
+        else:
+            # Entity introduced in IFC4
+            # definition.is_a('IfcPreDefinedPropertySet'):
+            for prop in range(4, len(definition)):
+                props[definition.attribute_name(prop)] = definition[prop]
+        return props