1 files changed, 26 insertions, 18 deletions
diff --git a/source/blender/functions/FN_multi_function_param_type.hh b/source/blender/functions/FN_multi_function_param_type.hh
index 69ac4c2382e..8a7284624d1 100644
--- a/source/blender/functions/FN_multi_function_param_type.hh
+++ b/source/blender/functions/FN_multi_function_param_type.hh
@@ -22,6 +22,23 @@
 
 namespace blender::fn {
 
+enum class MFParamCategory {
+  SingleInput,
+  VectorInput,
+  SingleOutput,
+  VectorOutput,
+  SingleMutable,
+  VectorMutable,
+};
+
+template<MFParamCategory Category, typename T> struct MFParamTag {
+  static constexpr MFParamCategory category = Category;
+  using base_type = T;
+  /* TODO: Doesn't support all categories yet, this can be generalized when necessary. */
+  using array_type =
+      std::conditional_t<Category == MFParamCategory::SingleInput, VArray<T>, MutableSpan<T>>;
+};
+
 class MFParamType {
  public:
   enum InterfaceType {
@@ -30,15 +47,6 @@ class MFParamType {
     Mutable,
   };
 
-  enum Category {
-    SingleInput,
-    VectorInput,
-    SingleOutput,
-    VectorOutput,
-    SingleMutable,
-    VectorMutable,
-  };
-
  private:
   InterfaceType interface_type_;
   MFDataType data_type_;
@@ -89,34 +97,34 @@ class MFParamType {
     return interface_type_;
   }
 
-  Category category() const
+  MFParamCategory category() const
   {
     switch (data_type_.category()) {
       case MFDataType::Single: {
         switch (interface_type_) {
           case Input:
-            return SingleInput;
+            return MFParamCategory::SingleInput;
           case Output:
-            return SingleOutput;
+            return MFParamCategory::SingleOutput;
           case Mutable:
-            return SingleMutable;
+            return MFParamCategory::SingleMutable;
         }
         break;
       }
       case MFDataType::Vector: {
         switch (interface_type_) {
           case Input:
-            return VectorInput;
+            return MFParamCategory::VectorInput;
           case Output:
-            return VectorOutput;
+            return MFParamCategory::VectorOutput;
           case Mutable:
-            return VectorMutable;
+            return MFParamCategory::VectorMutable;
         }
         break;
       }
     }
-    BLI_assert(false);
-    return SingleInput;
+    BLI_assert_unreachable();
+    return MFParamCategory::SingleInput;
   }
 
   bool is_input_or_mutable() const