New system module with UI to browse systems in an IFC.

src/ifcopenshell-python/ifcopenshell/api/system/add_system.py

@@ -0,0 +1,17 @@
+import ifcopenshell
+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        return self.file.create_entity("IfcSystem", **{
+            "GlobalId": ifcopenshell.guid.new(),
+            "OwnerHistory": ifcopenshell.api.run("owner.create_owner_history", self.file),
+            "Name": "Unnamed"
+        })

src/ifcopenshell-python/ifcopenshell/api/system/assign_system.py

@@ -0,0 +1,27 @@
+import ifcopenshell
+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {
+            "product": None,
+            "system": None,
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        if not self.settings["system"].IsGroupedBy:
+            return self.file.create_entity("IfcRelAssignsToGroup", **{
+                "GlobalId": ifcopenshell.guid.new(),
+                "OwnerHistory": ifcopenshell.api.run("owner.create_owner_history", self.file),
+                "RelatedObjects": [self.settings["product"]],
+                "RelatingGroup": self.settings["system"]
+            })
+        rel = self.settings["system"].IsGroupedBy[0]
+        related_objects = set(rel.RelatedObjects) or set()
+        related_objects.add(self.settings["product"])
+        rel.RelatedObjects = list(related_objects)
+        ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": rel})

src/ifcopenshell-python/ifcopenshell/api/system/data.py

@@ -0,0 +1,24 @@
+class Data:
+    is_loaded = False
+    products = {}
+    systems = {}
+
+    @classmethod
+    def purge(cls):
+        cls.is_loaded = False
+        cls.products = {}
+        cls.systems = {}
+
+    @classmethod
+    def load(cls, file):
+        cls.products = {}
+        cls.systems = {}
+        for system in file.by_type("IfcSystem", include_subtypes=False):
+            if system.IsGroupedBy:
+                for rel in system.IsGroupedBy:
+                    for product in rel.RelatedObjects:
+                        cls.products.setdefault(product.id(), []).append(system.id())
+            data = system.get_info()
+            del data["OwnerHistory"]
+            cls.systems[system.id()] = data
+        cls.is_loaded=True

src/ifcopenshell-python/ifcopenshell/api/system/edit_system.py

@@ -0,0 +1,13 @@
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {
+            "system": None,
+            "attributes": {}
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        for name, value in self.settings["attributes"].items():
+            setattr(self.settings["system"], name, value)

src/ifcopenshell-python/ifcopenshell/api/system/remove_system.py

@@ -0,0 +1,11 @@
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"system": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        for rel in self.settings["system"].IsGroupedBy or []:
+            self.file.remove(rel)
+        self.file.remove(self.settings["system"])

src/ifcopenshell-python/ifcopenshell/api/system/unassign_system.py

@@ -0,0 +1,25 @@
+import ifcopenshell
+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {
+            "product": None,
+            "system": None,
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        if not self.settings["system"].IsGroupedBy:
+            return
+        rel = self.settings["system"].IsGroupedBy[0]
+        related_objects = set(rel.RelatedObjects) or set()
+        related_objects.remove(self.settings["product"])
+        if len(related_objects):
+            rel.RelatedObjects = list(related_objects)
+            ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": rel})
+        else:
+            self.file.remove(rel)