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POAda Generic Package with Default Subprogram
 

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    <p>I am trying to create an Ada generic package that has a subprogram parameter with a default value. I cant get the compiler to recognize the default value.. Im guessing this is due to visibility. Is there a way to forward declare a function within the generic declaration?</p> <p>The Generic Spec:</p> <pre><code>generic type Item is private; type Item_Ref is access all Item; Addr : System.Address; Default : Item; with Is_Valid (Obj : Item) return Boolean; -- Forward Declare ** DOES NOT COMPILE function Default_Validate (Data_Ptr : Item_Ref) return Boolean; with function Validate (Data_Ptr : Item_Ref) return Boolean is Default_Validate; package Foo is -- function Default_Validate (Data_Ptr : Item_Ref) return Boolean; function Read_Eeprom return Item; end Foo; </code></pre> <p>The Generic Body:</p> <pre><code>package body Foo is Obj : aliased Item; for Obj'Address use Addr; -- Read Method function Read_Eeprom return Item is begin -- ** Read EEPROM using OBJ ** Validate (Obj'Unchecked_Access); end Read_Eeprom; -- Default Validate Method function Default_Validate (Data_Ptr : Item_Ref) return Boolean is Valid : Boolean; begin Valid := Is_Valid(Data_Ptr.all); if not Valid then Data_Ptr.all := Default; end if; return Valid; end Default_Validate; end Foo; </code></pre> <p>Driver</p> <pre><code>with Foo; procedure Main is MAX_INT : constant Integer := 100; MIN_INT : constant Integer := 0; -- Special / Non-Scaler Type type Pair_Type is record X : Integer; Y : Integer; end record; type Pair_Ref is access all Pair; -- Is Valid function Int_Is_Valid(Int : Integer) return Boolean is begin return (Int &lt;= MAX_INT and Int &gt;= MIN_INT); end Pair_Is_Valid; -- Is Valid function Pair_Is_Valid(Pair : Pair_Type) return Boolean is begin return Pair.X'Valid and Pair.Y'Valid; end Pair_Is_Valid; -- Validate function Pair_Validate(Pair : Pair_Ref) return Boolean is Valid : Boolean := True; begin if not Pair.X'Valid then Pair.X := 0; Valid := False; end if; if not Pair.Y'Valid then Pair.Y := 0; Valid := False; end if; return Valid; end Special_Validate; type Int_Ref is access all Integer; My_Int : Integer; My_Pair : Pair_Type; Default_Pair : Pair_Type := (0,0); package Int_Obj is new Foo (Item =&gt; Integer, Item_Ref =&gt; Int_Ref, Addr =&gt; My_Int'Address, Default =&gt; 0, Is_Valid =&gt; Int_Is_Valid); package Pair_Obj is new Foo (Item =&gt; Pair_Type, Item_Ref =&gt; Pair_Ref, Addr =&gt; My_Pair'Address, Default =&gt; Default_Pair, Is_Valid =&gt; Pair_Is_Valid, Validate =&gt; Pair_Validate); Tmp_Int : Integer; Tmps_Pair : Pair_Type; begin Tmp_Int := Int_Obj.Read_Eeprom; Tmp_Pair := Pair_Obj.Read_Eeprom; end Main; </code></pre> <p>The error Im getting is "end of file expected, file can only have one compilation unit" How can I default a generic subprogram to a function that is a member of the package?</p>
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