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

    ------------------------------------------------------------------------------
    --                                                                          --
    --                           GNAT ncurses Binding                           --
    --                                                                          --
    --           Terminal_Interface.Curses.Forms.Field_Types.User.Choice        --
    --                                                                          --
    --                                 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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    -- 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               --
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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:  Juergen Pfeifer, 1996
    --  Version Control:
    --  @Revision: 1.11 @
    --  Binding Version 01.00
    ------------------------------------------------------------------------------
    with Interfaces.C;

    package Terminal_Interface.Curses.Forms.Field_Types.User.Choice is
       pragma Preelaborate
         (Terminal_Interface.Curses.Forms.Field_Types.User.Choice);

       use type Interfaces.C.int;
       subtype C_Int is Interfaces.C.int;

       type User_Defined_Field_Type_With_Choice is abstract new
         User_Defined_Field_Type with null record;
       --  This is the root of the mechanism we use to create field types in
       --  Ada95 that allow the prev/next mechanism. You should your own type
       --  derive from this one and implement the Field_Check, Character_Check
       --  Next and Previous functions for your own type.

       type User_Defined_Field_Type_With_Choice_Access is access all
         User_Defined_Field_Type_With_Choice'Class;

       function Next
         (Fld : Field;
          Typ : User_Defined_Field_Type_With_Choice) return Boolean
          is abstract;
       --  If True is returned, the function successfully generated a next
       --  value into the fields buffer.

       function Previous
         (Fld : Field;
          Typ : User_Defined_Field_Type_With_Choice) return Boolean
          is abstract;
       --  If True is returned, the function successfully generated a previous
       --  value into the fields buffer.

       --  +----------------------------------------------------------------------
       --  | Private Part.
       --  |
    private
       use type Interfaces.C.int;

       function C_Generic_Choice return C_Field_Type;

       function Generic_Next (Fld : Field;
                              Usr : System.Address) return C_Int;
       pragma Convention (C, Generic_Next);
       --  This is the generic next Choice_Function for the low-level fieldtype
       --  representing all the User_Defined_Field_Type derivates. It routes
       --  the call to the Next implementation for the type.

       function Generic_Prev (Fld : Field;
                              Usr : System.Address) return C_Int;
       pragma Convention (C, Generic_Prev);
       --  This is the generic prev Choice_Function for the low-level fieldtype
       --  representing all the User_Defined_Field_Type derivates. It routes
       --  the call to the Previous implementation for the type.

    end Terminal_Interface.Curses.Forms.Field_Types.User.Choice;