feat: Set string settings with allowed values via string constants

doc/changelog.d/4190.added.md

@@ -0,0 +1 @@
+Set string settings with allowed values via string constants

src/ansys/fluent/core/codegen/settingsgen.py

@@ -38,6 +38,7 @@
     ListObject,
     NamedObject,
     get_cls,
+    to_constant_name,
     to_python_name,
 )
 from ansys.fluent.core.utils.fix_doc import fix_settings_doc
@@ -151,6 +152,7 @@ def _populate_data(cls, api_tree: dict, version: str) -> dict:
         data["child_object_type"]["doc"] = f"'child_object_type' of {cls.__name__}."
     else:
         data["child_object_type"] = None
+    data["allowed_values"] = getattr(cls, "_allowed_values", [])
     return data
 
 
@@ -307,7 +309,15 @@ def _write_data(cls_name: str, python_name: str, data: dict, f: IO, f_stub: IO |
     if return_type:
         s.write(f"    return_type = {return_type!r}\n")
         s_stub.write("    return_type: str\n")
+    for allowed_value in data["allowed_values"]:
+        s.write(
+            f"    {to_constant_name(allowed_value)} = _FlStringConstant({allowed_value!r})\n"
+        )
+        s_stub.write(
+            f"    {to_constant_name(allowed_value)}: Final[str] = {allowed_value!r}\n"
+        )
     s.write("\n")
+    s_stub.write("\n")
     for name, (python_name, data, hash_, should_write_stub) in classes_to_write.items():
         if name not in _CLASS_WRITTEN:
             _write_data(
@@ -371,10 +381,11 @@ def generate(version: str, static_infos: dict, verbose: bool = False) -> None:
         header.write("    _InputFile,\n")
         header.write("    _OutputFile,\n")
         header.write("    _InOutFile,\n")
+        header.write("    _FlStringConstant,\n")
         header.write(")\n\n")
         f.write(header.getvalue())
         f_stub.write(header.getvalue())
-        f_stub.write("from typing import Any\n\n")
+        f_stub.write("from typing import Any, Final\n\n")
         f.write(f'SHASH = "{shash}"\n\n')
         name = data["name"]
         _NAME_BY_HASH[_gethash(data)] = name

src/ansys/fluent/core/services/settings.py

@@ -335,6 +335,7 @@ def get_static_info(self) -> dict[str, Any]:
         """
         request = SettingsModule.GetStaticInfoRequest()
         request.root = "fluent"
+        request.optional_attrs.append("allowed-values")
         response = self._service_impl.get_static_info(request)
         # The RPC calls no longer raise an exception. Force an exception if
         # type is empty

src/ansys/fluent/core/solver/flobject.py

@@ -55,6 +55,7 @@
 import types
 from typing import (
     Any,
+    Callable,
     Dict,
     ForwardRef,
     Generic,
@@ -187,7 +188,7 @@ def assert_type(val, tp):
 def to_python_name(fluent_name: str) -> str:
     """Convert a scheme string to a Python variable name.
 
-    This function replaces symbols with _. Any ``?`` symbols are
+    This function replaces symbols with _. ``'`` and ``?`` symbols are
     ignored.
     """
     if not fluent_name:
@@ -198,6 +199,20 @@ def to_python_name(fluent_name: str) -> str:
     return name
 
 
+def to_constant_name(fluent_name: str) -> str:
+    """Convert a scheme string to a Python constant name.
+
+    This function replaces symbols and spaces with _ and converts the name to uppercase.
+    ``'`` and ``?`` symbols are ignored.
+    """
+    fluent_name = fluent_name.replace(" ", "_")
+    name = fluent_name.translate(_ttable).upper()
+    if name[0].isdigit():
+        # If the first character is a digit, prepend "CASE_"
+        name = "CASE_" + name
+    return name
+
+
 _to_field_name_str = naming_strategy().to_string
 
 
@@ -2029,6 +2044,33 @@ def allowed_values(self):
             return []
 
 
+class _MaybeActiveString(str):
+    """A string class with an is_active() method."""
+
+    def __new__(cls, value, is_active: Callable[[], bool]):
+        return super().__new__(cls, value)
+
+    def __init__(self, value, is_active: Callable[[], bool]):
+        super().__init__()
+        self.is_active = is_active
+
+
+class _FlStringConstant:
+    """A descriptor class to hold a constant string value."""
+
+    def __init__(self, value):
+        self._value = value
+
+    def __get__(self, instance, owner):
+        def is_active():
+            return self._value in instance.allowed_values()
+
+        return _MaybeActiveString(self._value, is_active=is_active)
+
+    def __set__(self, instance, value):
+        raise AttributeError("Cannot set a constant value.")
+
+
 _bases_by_class = {}
 
 
@@ -2217,6 +2259,16 @@ def _process_cls_names(info_dict, names, write_doc=False):
                     k,
                 )
 
+        allowed_values = info.get("allowed-values") or info.get("allowed_values", [])
+        if allowed_values:
+            for allowed_value in allowed_values:
+                setattr(
+                    cls,
+                    to_constant_name(allowed_value),
+                    _FlStringConstant(allowed_value),
+                )
+            cls._allowed_values = allowed_values
+
     except Exception:
         print(
             f"Unable to construct class for '{name}' of "

tests/test_codegen.py

@@ -504,6 +504,7 @@ def _get_query_settings_static_info(name, args):
     _InputFile,
     _OutputFile,
     _InOutFile,
+    _FlStringConstant,
 )
 
 SHASH = "3e6d76a4601701388ea8258912d145b7b7c436699a50b6c7fe9a29f41eeff194"

tests/test_settings_api.py

@@ -27,6 +27,7 @@
 
 from ansys.fluent.core.examples import download_file
 from ansys.fluent.core.pyfluent_warnings import PyFluentUserWarning
+from ansys.fluent.core.solver import Viscous
 from ansys.fluent.core.solver.flobject import (
     DeprecatedSettingWarning,
     _Alias,
@@ -762,3 +763,28 @@ def test_runtime_python_classes(
         ].general.material()
         == "water-liquid"
     )
+
+
+@pytest.mark.fluent_version(">=26.1")
+def test_setting_string_constants(mixing_elbow_settings_session):
+    solver = mixing_elbow_settings_session
+    viscous = Viscous(solver)
+
+    # viscous.model.INVISCID is a string constant
+    assert viscous.model.INVISCID == "inviscid"
+    assert isinstance(viscous.model.INVISCID, str)
+    with pytest.raises(AttributeError):
+        viscous.model.INVISCID = "invalid"
+
+    # Setting using string constants
+    viscous.model = viscous.model.INVISCID
+    assert viscous.model() == "inviscid"
+    viscous.model = viscous.model.K_EPSILON
+    assert viscous.model() == "k-epsilon"
+    viscous.k_epsilon_model = viscous.k_epsilon_model.RNG
+    assert viscous.k_epsilon_model.RNG.is_active() is True
+    assert viscous.k_epsilon_model() == "rng"
+    assert viscous.k_epsilon_model.EASM.is_active() is False
+
+    with pytest.raises(ValueError):
+        viscous.k_epsilon_model = viscous.k_epsilon_model.EASM