* Adjust logic: add formal parameter to decide wether we

          should exit or not.

          For openaadl/ocarina#224

src/core/instance/ocarina-instances.adb

@@ -146,7 +146,10 @@ package body Ocarina.Instances is
    -- Instantiate_Model --
    -----------------------
 
-   function Instantiate_Model (Root : Node_Id) return Node_Id is
+   function Instantiate_Model (Root : Node_Id;
+                               Exit_If_Error : Boolean := True)
+                              return Node_Id
+   is
       pragma Assert (Kind (Root) = K_AADL_Specification);
 
       Root_Systems  : Node_List;
@@ -222,7 +225,8 @@ package body Ocarina.Instances is
 
          if No (Root_System) then
             Error_Loc (1) := No_Location;
-            Exit_On_Error (True, "Cannot find a root system");
+            Exit_On_Error (Exit_If_Error, "Cannot find a root system");
+            return No_Node;
          end if;
 
          if Root_System_Name /= No_Name
@@ -238,7 +242,7 @@ package body Ocarina.Instances is
               (Root_System, False, True);
             DE ("system % is not a root system, use %");
             Root_System := No_Node;
-            Exit_On_Error (True, "Cannot instantiate AADL model");
+            Exit_On_Error (Exit_If_Error, "Cannot instantiate AADL model");
          end if;
       end if;
 
@@ -248,7 +252,9 @@ package body Ocarina.Instances is
 
       if No (Root_System) then
          Instance_Root := No_Node;
-         Exit_On_Error (True, "Cannot instantiate full model, exit now");
+         Exit_On_Error (Exit_If_Error,
+                        "Cannot instantiate full model, exit now");
+         return No_Node;
       else
          --  The first step of the instantiation consist of propagate the
          --  properties declared in the AADL packages to the AADL

src/core/instance/ocarina-instances.ads

@@ -33,12 +33,17 @@ with Ocarina.Types; use Ocarina.Types;
 
 package Ocarina.Instances is
 
-   function Instantiate_Model (Root : Node_Id) return Node_Id;
+   function Instantiate_Model
+     (Root : Node_Id;
+      Exit_If_Error : Boolean := True)
+     return Node_Id;
    --  Instantiate the tree of the model and return the instantiated
-   --  architecture. If Root_System_Name in Ocarina.Options is set and
-   --  corresponds to a root system eligible for instantiation, then
-   --  instantiate the model from this system.
-   --  FIXME : not clear
+   --  architecture. If Root_System_Name (from Ocarina.Options) is set
+   --  and corresponds to a root system eligible for instantiation,
+   --  then instantiate the model from this system.  If Exit_If_Error
+   --  is set to true, exit immediatly in case of an error, otherwise
+   --  return No_Node.
+   --
    --  If Root_System_Name does not correspond to anything,
    --  instantiate nothing. Root_System_Name is to be used when
    --  several system implementations are electible.