# File : terminal_interface-curses-forms-field_types-user.ads

    ------------------------------------------------------------------------------
    --                                                                          --
    --                           GNAT ncurses Binding                           --
    --                                                                          --
    --               Terminal_Interface.Curses.Forms.Field_Types.User           --
    --                                                                          --
    --                                 S P E C                                  --
    --                                                                          --
    ------------------------------------------------------------------------------
    -- Copyright 2020 Thomas E. Dickey                                          --
    -- Copyright 1999-2009,2011 Free Software Foundation, Inc.                  --
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    -- The above copyright notice and this permission notice shall be included  --
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    ------------------------------------------------------------------------------
    --  Author:  Juergen Pfeifer, 1996
    --  Version Control:
    --  @Revision: 1.16 @
    --  @Date: 2020/02/02 23:34:34 @
    --  Binding Version 01.00
    ------------------------------------------------------------------------------
    with Interfaces.C;

    package Terminal_Interface.Curses.Forms.Field_Types.User is
       pragma Preelaborate (Terminal_Interface.Curses.Forms.Field_Types.User);
       subtype C_Int is Interfaces.C.int;

       type User_Defined_Field_Type is abstract new Field_Type with null record;
       --  This is the root of the mechanism we use to create field types in
       --  Ada95. You should your own type derive from this one and implement
       --  the Field_Check and Character_Check functions for your own type.

       type User_Defined_Field_Type_Access is access all
         User_Defined_Field_Type'Class;

       function Field_Check
         (Fld : Field;
          Typ : User_Defined_Field_Type) return Boolean
          is abstract;
       --  If True is returned, the field is considered valid, otherwise it is
       --  invalid.

       function Character_Check
         (Ch  : Character;
          Typ : User_Defined_Field_Type) return Boolean
          is abstract;
       --  If True is returned, the character is considered as valid for the
       --  field, otherwise as invalid.

       procedure Set_Field_Type (Fld : Field;
                                 Typ : User_Defined_Field_Type);
       --  This should work for all types derived from User_Defined_Field_Type.
       --  No need to reimplement it for your derived type.

       --  +----------------------------------------------------------------------
       --  | Private Part.
       --  | Used by the Choice child package.
    private
       function C_Generic_Type   return C_Field_Type;

       function Generic_Field_Check (Fld : Field;
                                     Usr : System.Address) return Curses_Bool;
       pragma Convention (C, Generic_Field_Check);
       --  This is the generic Field_Check_Function for the low-level fieldtype
       --  representing all the User_Defined_Field_Type derivatives. It routes
       --  the call to the Field_Check implementation for the type.

       function Generic_Char_Check (Ch  : C_Int;
                                    Usr : System.Address) return Curses_Bool;
       pragma Convention (C, Generic_Char_Check);
       --  This is the generic Char_Check_Function for the low-level fieldtype
       --  representing all the User_Defined_Field_Type derivatives. It routes
       --  the call to the Character_Check implementation for the type.

    end Terminal_Interface.Curses.Forms.Field_Types.User;