Fix CppType factory: Fix cloning in `(de)constify`, enable immediate creation of `ref`s

src/pystencilssfg/lang/types.py

+from __future__ import annotations
 from typing import Any, Iterable
 from abc import ABC
 from pystencils.types import PsType, PsPointerType, PsCustomType
@@ -50,16 +51,26 @@ def cpptype(typestr: str, include: str | HeaderFile | Iterable[str | HeaderFile]
     class TypeClass(CppType):
         includes = frozenset(HeaderFile.parse(h) for h in headers)
 
-        def __init__(self, *template_args, const: bool = False, **template_kwargs):
+    class TypeClassFactory(TypeClass):
+        def __new__(  # type: ignore
+            cls,
+            *template_args,
+            const: bool = False,
+            ref: bool = False,
+            **template_kwargs,
+        ) -> PsType:
             template_args = tuple(_fixarg(arg) for arg in template_args)
             template_kwargs = {
                 key: _fixarg(value) for key, value in template_kwargs.items()
             }
 
             name = typestr.format(*template_args, **template_kwargs)
-            super().__init__(name, const)
+            obj: PsType = TypeClass(name, const)
+            if ref:
+                obj = Ref(obj)
+            return obj
 
-    return TypeClass
+    return TypeClassFactory
 
 
 class Ref(PsType):

tests/lang/test_types.py

-from pystencilssfg.lang import cpptype, HeaderFile
+from pystencilssfg.lang import cpptype, HeaderFile, Ref, strip_ptr_ref
 from pystencils import create_type
+from pystencils.types import constify, deconstify
 
 
 def test_cpptypes():
@@ -12,3 +13,23 @@ def test_cpptypes():
         == vec_type.includes
         == {HeaderFile("vector", system_header=True)}
     )
+
+    assert deconstify(constify(vec_type)) == vec_type
+
+
+def test_cpptype_const():
+    tclass = cpptype("std::vector< {T} >", "<vector>")
+
+    vec_type = tclass(T=create_type("uint32"))
+    assert constify(vec_type) == tclass(T=create_type("uint32"), const=True)
+
+    vec_type = tclass(T=create_type("uint32"), const=True)
+    assert deconstify(vec_type) == tclass(T=create_type("uint32"), const=False)
+
+
+def test_cpptype_ref():
+    tclass = cpptype("std::vector< {T} >", "<vector>")
+
+    vec_type = tclass(T=create_type("uint32"), ref=True)
+    assert isinstance(vec_type, Ref)
+    assert strip_ptr_ref(vec_type) == tclass(T=create_type("uint32"))