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PORecord containing access to instantiation of generic package based on that record
 

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    <p>This is really an annoying problem. I have a record type that wraps various base types and now I need it to be able to store a vector (from Ada.Containers.Vectors) <em>in itself</em>! I guess that's not possible but can anyone give me advice on how to solve this problem in another way perhaps? To give you a better idea of what I'm up to, here is what does <em>not</em> work:</p> <pre><code>with Base_Types; use Base_Types; with Ada.Strings.Wide_Unbounded; use Ada.Strings.Wide_Unbounded; with Ada.Containers.Vectors; with Green_Tasks; use Green_Tasks; with Ada.Unchecked_Deallocation; package Boxed_Types is type String_Ptr is access Unbounded_Wide_String; procedure Free_Unbounded_Wide_String is new Ada.Unchecked_Deallocation (Object =&gt; Unbounded_Wide_String, Name =&gt; String_Ptr); type Vector_Ptr; -- this won't work type Type_T is (T_Null, T_UInt64, T_Text, T_Bool, T_GTask, T_Vector); type Item (IType : Type_T := T_Null) is record case IType is when T_Null =&gt; null; when T_UInt64 =&gt; UInt64 : UInteger_64; when T_Text =&gt; String : String_Ptr; when T_Bool =&gt; Bool : Boolean; when T_GTask =&gt; Green_Task : Green_Task_Ptr; when T_Vector =&gt; Item_Vector : Vector_Ptr; -- error here end case; end record; package Item_Vectors is new Ada.Containers.Vectors (Index_Type =&gt; Natural, Element_Type =&gt; Item); use Item_Vectors; type Vector_Ptr is access Vector; end Boxed_Types; </code></pre> <p>This gives me the not so unexpected error <em>"invalid use of type before it's full declaration"</em> for Vector_Ptr. However, I cannot instantiate the vector package before I have declared Item either, and I really need the vector and the base types wrapped into one record type. (It's for Interpreter I'm writing in my spare time; the VM must store various different types on the stack, in heterogenous arrays, manipulate them, etc..) </p> <p>Will I have to break type safety entirely and mess around with address to access conversions or is there a cleaner solution?</p>
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