model_utils: add MAttribute::is_nullable

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --git a/src/model_utils.nit b/src/model_utils.nit
index f893b8d..12b8907 100644 (file)
--- a/src/model_utils.nit
+++ b/src/model_utils.nit
@@ -255,6 +255,15 @@ redef class MClass
        end
 end
 
+redef class MAttribute
+       # Is this attribute nullable for sure?
+       #
+       # This mean that its introduction is declarred with a nullable static type
+       # since attributes are invariant this will work on most cases
+       # attributes with static type anchored with a virtual type are not "nullable for-sure"
+       # because this type can be redefined in subclasses
+       fun is_nullable: Bool do return intro.static_mtype isa MNullableType
+end
 
 # Sorters