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

    ------------------------------------------------------------------------------
    --                                                                          --
    --                           GNAT ncurses Binding                           --
    --                                                                          --
    --               Terminal_Interface.Curses.Forms.Field_Types.User           --
    --                                                                          --
    --                                 S P E C                                  --
    --                                                                          --
    ------------------------------------------------------------------------------
    -- Copyright (c) 1998 Free Software Foundation, Inc.                        --
    --                                                                          --
    -- Permission is hereby granted, free of charge, to any person obtaining a  --
    -- copy of this software and associated documentation files (the            --
    -- "Software"), to deal in the Software without restriction, including      --
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    -- distribute, distribute with modifications, sublicense, and/or sell       --
    -- copies of the Software, and to permit persons to whom the Software is    --
    -- furnished to do so, subject to the following conditions:                 --
    --                                                                          --
    -- The above copyright notice and this permission notice shall be included  --
    -- in all copies or substantial portions of the Software.                   --
    --                                                                          --
    -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  --
    -- OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               --
    -- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   --
    -- IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   --
    -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    --
    -- OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    --
    -- THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               --
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    -- Except as contained in this notice, the name(s) of the above copyright   --
    -- holders shall not be used in advertising or otherwise to promote the     --
    -- sale, use or other dealings in this Software without prior written       --
    -- authorization.                                                           --
    ------------------------------------------------------------------------------
    --  Author: Jürgen Pfeifer <<juergen.pfeifer@gmx.net>> 1996
    --  Version Control:
    --  @Revision: 1.9 @
    --  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);
       use type Interfaces.C.int;
       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 : in Field;
                                 Typ : in 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
       use type Interfaces.C.int;

       function C_Generic_Type   return C_Field_Type;

       function Generic_Field_Check (Fld : Field;
                                     Usr : System.Address) return C_Int;
       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 derivates. It routes
       --  the call to the Field_Check implementation for the type.

       function Generic_Char_Check (Ch  : C_Int;
                                    Usr : System.Address) return C_Int;
       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 derivates. It routes
       --  the call to the Character_Check implementation for the type.

    end Terminal_Interface.Curses.Forms.Field_Types.User;