nitvm: Introduces a type which represents initial values inside attributes

Signed-off-by: Julien Pagès <julien.projet@gmail.com>

diff --git a/src/vm.nit b/src/vm.nit
index b5e5bb8..fd27117 100644 (file)
--- a/src/vm.nit
+++ b/src/vm.nit
@@ -44,6 +44,16 @@ class VirtualMachine super NaiveInterpreter
        # Handles memory and garbage collection
        var memory_manager: MemoryManager = new MemoryManager
 
+       # The unique instance of the `MInit` value
+       var initialization_value: Instance
+
+       init(modelbuilder: ModelBuilder, mainmodule: MModule, arguments: Array[String])
+       do
+               super
+               var init_type = new MInitType(mainmodule.model)
+               initialization_value = new MutableInstance(init_type)
+       end
+
        # Subtyping test for the virtual machine
        redef fun is_subtype(sub, sup: MType): Bool
        do
@@ -458,6 +468,29 @@ redef class MutableInstance
        var internal_attributes: Pointer
 end
 
+# Is the type of the initial value inside attributes
+class MInitType
+       super MType
+
+       redef var model: Model
+       protected init(model: Model)
+       do
+               self.model = model
+       end
+
+       redef fun to_s do return "InitType"
+       redef fun as_nullable do return self
+       redef fun need_anchor do return false
+       redef fun resolve_for(mtype, anchor, mmodule, cleanup_virtual) do return self
+       redef fun can_resolve_for(mtype, anchor, mmodule) do return true
+
+       redef fun collect_mclassdefs(mmodule) do return new HashSet[MClassDef]
+
+       redef fun collect_mclasses(mmodule) do return new HashSet[MClass]
+
+       redef fun collect_mtypes(mmodule) do return new HashSet[MClassType]
+end
+
 # A VTable contains the virtual method table for the dispatch
 # and informations to perform subtyping tests
 class VTable