util.schema: dedupe inline schema resolution logic

src/ifcopenshell-python/ifcopenshell/__init__.py

@@ -305,12 +305,13 @@ def schema_by_name(
         you are testing non-ISO IFC releases.
     :return: Schema definition object.
     """
+    import ifcopenshell.util.schema
+
     assert schema_version or schema, "Either schema or schema_version must be specified."
     if schema_version:
-        prefixes = ("IFC", "X", "_ADD", "_TC")
+        schema = ifcopenshell.util.schema.get_schema_name_from_version(schema_version)
-        schema = "".join("".join(map(str, t)) if t[1] else "" for t in zip(prefixes, schema_version))
     else:
-        schema = {"IFC4X3": "IFC4X3_ADD2"}.get(schema, schema)
+        schema = ifcopenshell.util.schema.get_schema_identifier(schema)
     return ifcopenshell_wrapper.schema_by_name(schema)
 
 

src/ifcopenshell-python/ifcopenshell/file.py

@@ -594,11 +594,12 @@ class file:
             # A poweruser testing out a particular version of IFC4X3
             model = ifcopenshell.file(schema_version=(4, 3, 0, 1))
         """
+        import ifcopenshell.util.schema
+
         if schema_version:
-            prefixes = ("IFC", "X", "_ADD", "_TC")
+            schema = ifcopenshell.util.schema.get_schema_name_from_version(schema_version)
-            schema = "".join("".join(map(str, t)) if t[1] else "" for t in zip(prefixes, schema_version))
         else:
-            schema = {"IFC4X3": "IFC4X3_ADD2"}.get(schema, schema)
+            schema = ifcopenshell.util.schema.get_schema_identifier(schema)
         if f is not None:
             self.wrapped_data = f
             if not f.good():

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

@@ -50,6 +50,21 @@ def get_fallback_schema(version: str) -> IFC_SCHEMA:
     return version
 
 
+def get_schema_identifier(schema: IFC_SCHEMA) -> str:
+    """Resolve a general schema name to the specific identifier used internally
+    (as in ``file.schema_identifier``).
+
+    E.g. ``IFC4X3`` -> ``IFC4X3_ADD2``.
+    """
+    return {"IFC4X3": "IFC4X3_ADD2"}.get(schema, schema)
+
+
+def get_schema_name_from_version(schema_version: tuple[int, ...]) -> str:
+    """Build a schema name from a version tuple, e.g. (4, 3, 0, 1) -> "IFC4X3_TC1"."""
+    prefixes = ("IFC", "X", "_ADD", "_TC")
+    return "".join("".join(map(str, t)) if t[1] else "" for t in zip(prefixes, schema_version))
+
+
 def get_declaration(element: ifcopenshell.entity_instance):
     """Get the schema declaration of an actively used entity instance