Add API documentation for classification module

src/ifcopenshell-python/ifcopenshell/api/classification/add_reference.py

@@ -21,18 +21,99 @@ import ifcopenshell.util.schema
 
 
 class Usecase:
-    def __init__(self, file, **settings):
+    def __init__(self, file, product=None, reference=None, identification=None, name=None, classification=None, is_lightweight=True):
+        """Adds a new classification reference and assigns it to a product
+
+        A classification reference is a single entry such as "Pr_12_23_34" that
+        is part of an external classification system (such as Uniclass or
+        Omniclass).
+
+        References can be added to almost any object in IFC, including physical
+        objects, object types, properties, tasks, costs, resources, or even
+        resources such as profiles, documents, libraries, and so on.
+
+        Classification references can be added in two ways. Option 1) specify  a
+        custom arbitrary reference, where you have the manually specify the
+        identification (e.g. "Pr_12_23_45") and name (e.g. "Door Products").
+        Option 2) add a reference from an IFC classification library. The latter
+        is preferred if you are using a common classification system such as
+        Uniclass, as the library will be prepopulated with all the valid
+        classifications already.
+
+        Objects are allowed to have multiple classification references from
+        multiple classification systems. This means that adding a new reference
+        will not remove existing references.
+
+        References can be inherited from types. This means that if an
+        IfcWallType has a classification reference of Pr_12_23_34, then all
+        IfcWall occurrences of that type automatically get the same
+        classification of Pr_12_23_34. This means that it is more efficient to
+        assign to types where possible. If a classification reference is
+        assigned to both the type and an occurrence, then the assignment at the
+        occurrence will override the type classification.
+
+        :param product: The IFC object, property, or resource you want to
+            associate the classification reference to.
+        :type product: ifcopenshell.entity_instance.entity_instance
+        :param reference: The classification reference entity taken from an
+            IFC classification library. If you supply this parameter, you will
+            use option 2.
+        :type product: ifcopenshell.entity_instance.entity_instance, optional
+        :param identification: If you choose option 1 and do not specify a
+            reference, you may manually specify an identification code. The code
+            is typically a short identifier and may have punctuation to separate
+            the levels of hierarchy in the classificaion (e.g. Pr_12_23_34).
+        :type identification: str, optional
+        :param name: If you choose option 1 and do not specify a reference, you
+            may manually specify a name. The name is typically human readable.
+        :type name: str, optional
+        :param classification: The IfcClassification entity in your IFC model
+            (not the library, if you are doing option 2) that the reference is
+            part of.
+        :type product: ifcopenshell.entity_instance.entity_instance
+        :param is_lightweight: If you are doing option 2, choose whether or not
+            to only add that particular reference (lighweight) or also add all
+            of its parent references in the classification hierarchy (not
+            lighweight). For example, adding a lightweight reference to
+            Pr_12_23_34 will only add Pr_12_23_34, but adding a heavy reference
+            to Pr_12_23_34 will also add Pr_12_23 and Pr_12. These parent
+            references merely help describe the "tree" of classifications, but
+            is generally unnecessary. Using lightweight classifications are
+            recommended and is the default.
+        :type is_lightweight: bool, optional
+        :return: The newly added IfcClassificationReference
+        :rtype: ifcopenshell.entity_instance.entity_instance
+
+        Example::
+
+            # Option 1: adding and assigning a new reference from scratch
+            wall_type = model.by_type("IfcWallType")[0]
+            classification = ifcopenshell.api.run("classification.add_classification",
+                model, classification="MyCustomClassification")
+            ifcopenshell.api.run("classification.add_reference", model,
+                product=wall_type, classification=classification,
+                identification="W_01", name="Interior Walls")
+
+            # Option 2: adding a popular classification from a library
+            library = ifcopenshell.open("/path/to/Uniclass.ifc")
+            lib_classification = library.by_type("IfcClassification")[0]
+            classification = ifcopenshell.api.run("classification.add_classification",
+                model, classification=lib_classification)
+            reference = [r for r in library.by_type("IfcClassificationReference")
+                if r.Identification == "XYZ"][0]
+            ifcopenshell.api.run("classification.add_reference", model,
+                product=wall_type, classification=classification,
+                reference=reference)
+        """
         self.file = file
         self.settings = {
-            "product": None,
-            "reference": None,
-            "identification": None,
-            "name": None,
-            "classification": None,
-            "is_lightweight": True,
+            "product": product,
+            "reference": reference,
+            "identification": identification,
+            "name": name,
+            "classification": classification,
+            "is_lightweight": is_lightweight,
         }
-        for key, value in settings.items():
-            self.settings[key] = value
 
     def execute(self):
         self.is_rooted = self.settings["product"].is_a("IfcRoot")