Add initial prototype.

3-mid/opengl/source/lean/shader/opengl-variable.ads

@@ -0,0 +1,28 @@
+with
+     GL;
+
+package openGL.Variable
+--
+--  Models a shader variable.
+--
+is
+   type Item  is abstract tagged private;
+
+
+   ---------
+   --  Forge
+   --
+
+   procedure define  (Self : in out Item);
+   procedure destroy (Self : in out Item);
+
+
+
+private
+
+   type Item is abstract tagged
+      record
+         gl_Variable : gl.GLint;
+      end record;
+
+end openGL.Variable;