You can now edit nested arithmetic cost values by using spreadsheet-like formulas

src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value_formula.py

@@ -0,0 +1,34 @@
+import ifcopenshell
+import ifcopenshell.util.cost
+import ifcopenshell.util.unit
+import ifcopenshell.util.element
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"cost_value": None, "formula": {}}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        try:
+            data = ifcopenshell.util.cost.unserialise_cost_value(self.settings["formula"], self.settings["cost_value"])
+        except:
+            return
+        self.edit_cost_value(data)
+
+    def edit_cost_value(self, data, parent=None):
+        ifc = data.get("ifc", None)
+        if not ifc:
+            ifc = ifcopenshell.api.run("cost.add_cost_value", self.file, parent=parent)
+        if "AppliedValue" in data:
+            if data["AppliedValue"]:
+                ifc.AppliedValue = self.file.createIfcMonetaryMeasure(data["AppliedValue"])
+            else:
+                ifc.AppliedValue = None
+        ifc.Category = data["Category"] if "Category" in data else None
+        ifc.ArithmeticOperator = data["ArithmeticOperator"] if "ArithmeticOperator" in data else None
+        if "Components" in data:
+            for component in data["Components"]:
+                self.edit_cost_value(component, ifc)

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

@@ -52,7 +52,7 @@ def unserialise_cost_value(formula, cost_value):
         result["ifc"] = element
         for i, component in enumerate(result.get("Components", [])):
             if element.Components and i < len(element.Components):
-                map_element_to_formula(element.Components[i], result["Components"][i])
+                map_element_to_result(element.Components[i], result["Components"][i])
     map_element_to_result(cost_value, result)
     return result
 
@@ -116,11 +116,14 @@ class CostValueUnserialiser:
     def get_operand(self, operand):
         child = operand.children[0]
         if child.data == "value":
-            return {"AppliedValue": self.get_value(child)}
+            value = self.get_value(child)
+            return {"AppliedValue": float(value) if value else None}
         elif child.data == "category":
             data = {}
             category = self.get_category(child)
             if category:
+                if category.lower() == "sum":
+                    category = "*"
                 data["Category"] = category
             formula = self.get_formula(operand.children[1])
             if formula.get("Components"):