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    Unit Misc;

    {
                                    MISC.PAS
                         A Turbo Vision Object Library

                                 By  Devin Cook
                                   MSD - 1990

    I haven't been exactly overwhelmed by the amount of Turbo Vision objects shared
    by TP users, so I thought I would thow my hat into the ring and spread a few
    objects I have developed around.

    I am not an expert in Turbo Vision ( who can be in 3 weeks? ), or in OOP, so I
    have probably broken quite a few rules, but you might get some ideas from the
    work I have done.

    This unit has some of the my more mainstream objects included.  I have a few
    other, less general objects which I may spread around later.

    These objects have not been used enough to verify they are 100% bug free, so
    if you find any problems, or have any comments, please send me some Email
    ( D.Cook on Genie ).

                                    OBJECTS:

    TDateView      -    A date text box, much like TClockView in TVDemos.

    TPushButton    -    A descendend of TButton, with "feel" for keyboard users.

    TNum_Box       -    A number only input box with an adjustable number of digits
                        before and after the decimal point, along with selectable
                        negative number acceptance.

    TLinked_Dialog -    A descendent of TDialog which allows you to set "Links"
                        between items ( i.e. item selection through cursor keys ).

    Also, FormatDate, a function used by TDateView is provided.

                                ÉÍÍÍÍÍÍÍÍÍÍÍÍÍ»
                                º  TDateView  º
                                ÈÍÍÍÍÍÍÍÍÍÍÍÍÍ¼

    TDateView is almost identicle to TClockView ( in TVDemos - Gadget.Pas ).

    INITIALIZATION:

    TDateView is initialized by sending TDateView a TRect giving it's location.

    USAGE:

    Once TDateView is initialized, an occasional call to TDateView.Update keeps
    the displayed date current.

    Example:

      Var TR    : TRect ;
          DateV : TDateView ;
      Begin
          TR.Assign( 60 , 0 , 78 , 1 );
          DateV.Init( TR );
          DateV.Update ;
      End;

                               ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
                               º  TPushButton  º
                               ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ¼

    TPushButton is identicle to TButton in every way except that when it is
    "pressed", it actually draws itself pressed.

    This gives visual feedback to those using non-mouse systems.

    The delay values in TPushButton.Press may need to be altered to adjust the
    "feel".

                                 ÉÍÍÍÍÍÍÍÍÍÍÍÍ»
                                 º  TNum_Box  º
                                 ÈÍÍÍÍÍÍÍÍÍÍÍÍ¼

    TNum_Box is a numerical entry box with definable precision.

    INITIALIZATION:

    TNum_Box is initialized by sending TNum_Box.Init:
            Location                            : TPoint
            Max Digits before the decimal point : Integer
            Max Digits after the decimal point  : Integer
            Negative Numbers allowed flag       : Boolean
            Default Value                       : Extended

    If the digits after the decimal point = 0, no decimal point is displayed
    ( or excepted ).

    If negative numbers are allowed, one extra space is reserved for a negative
    sign.  No digits can be entered in this spot.

    Only Backspace is used to edit the numberical field.

    USAGE:

    The value of the input box can be read directly from TNum_Box.Curr_Val.

    This value may not be up to date if editing is still taking place, or no
    data has been entered.  To ensure a correct reading, a call to
    TNum_Box.Update_Value is recommended.

    After initilization, the box is displayed with blanks for the number of digits.
    If you wish to display the default value instead, use TNum_Box.Update_Value.

    Example:

      Var TP        : TPoint ;
          Int_Box1  : TNum_Box ;
          Int_Box2  : TNum_Box ;
          Flt_Box1  : TNum_Box ;
      Begin
          Tp.X := 10 ;
          Tp.Y := 5 ;

          (* Define a box at 10,5 with 3 digits, no decimals, no negatives and a
             default of 0 *)

          Int_Box1.Init( TP , 3 , 0 , False , 0 )

          TP.X := 15 ;

          (* Define a box at 10,15 with 5 digits, no decimals, negatives and a
             default of 1.  Then, update the box displaying the default *)

          Int_Box2.Init( TP , 5 , 0 , True , 1 )
          Int_Box2.Update_Value ;

          TP.X := 25 ;

          (* Define a box at 10,25 with 5 digits, 2 decimal places , negatives and
             a default of 0.  Leave the box a blank. *)

          flt_Box1.Init( TP , 5 , 2 , True , 0 )

      End;

                              ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
                              º  TLinked_Dialog  º
                              ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ¼

    TLinked_Dialog is descendant of TDialog with improved cursor movement between
    fields.

    Developing for a non-mouse system ( even a mouse system ) where your dialogs
    have over about 10 fields gets a bit ugly.  The tab key becomes impracticle
    and setting hotkeys for each field may not be practicle.

    The program EXAMPLE.PAS is not an exageration, it is a SIMPLIFIED version of
    a dialog I am developing at work.  Try getting to a field #54 via tabs!

    TLinked_Dialog solves the problem by having the Dialog jump between links
    you define. Cursor keys are used to select the link direction, though 2 spare
    links are defined for object future use or for object use.

         Example of a linking:               11
                                             21 22
                                             31

      Object 21 would want links defined for 11 ( DLink_Up ), 22 ( DLink_Right ),
      and 31 ( DLink_Down ).

      Once the links are defined, HandleEvent switches the focus according to the
      cursor keys.

    INITIALIZATION:

    TDialog is initialized exactly the same as TDialog.  ( Refer to the Turbo Vision
    manual for details. )

    TLinked_Dialog.Init calls TDialog.Init and the initialized a collection of
    links to track item linking.

    USAGE:

    Once TLinked_Dialog is initialized, you insert items into the TLinked_Dialog
    just as you would a normal dialog.

    After the items are inserted, you set up links.

    *****  NOTE:  Do not set up links for an item before it is inserted! *****

    Links are created by calling TLinked_Dialog.Set_Link with
            Item to set link for    : PView
            Direction of link       : Integer
                                                  Use the constants:
                                          DLink_Up, Dlink_Down, DLink_Right,
                                          DLink_Left, DLink_Spare1, Dlink_Spare2
            Pointer to linked item  : Pointer

    All links are 1 way.  If you wish Button55 <--> Button56, you must define
    two links, Button55 right to Button56 and Button56 left to Button55.  This is
    because multiple items may be linked to the same item, which would make finding
    the reverse link impossible.

    You can select another object via a link by calling TLinked_Dialog.Select_Link
    with the link direction.  The currently selected object's link will be traced
    to the next object ( If possible ).

    Example:

      Var TR    : TRect ;
          TP    : TPoint ;
          TLD   : TLinked_Dialog ;
          Butt1 : TPushButton ;
          Box1  : TNum_Box ;
          Box2  : TNum_Box ;
          Box3  : TNum_Box ;
          Box4  : TNum_Box ;

      Begin
          TR.Assign( 10 , 1 , 70 , 10 );
          TLD.Init( TR ,'Test Linked Dialog');

          (* Set up a button and insert it *)

          TR.Assign( 5 , 3 , 15 , 5 );
          Butt1.Init(TR,'~P~ush',cmOk,bfDefault));
          TLD.Insert( Butt1 );

          (* Set up box1 and insert it *)
          TP.Y := 8 ;
          TP.X := 3 ;

          Box1.Init( TP , 3 , 2 , FALSE , 1 );
          TLD.Insert( Box1 );

          (* Set up box2 and insert it *)
          TP.X := TP.X + 10 ;

          Box2.Init( TP , 3 , 2 , FALSE , 1 );
          TLD.Insert( Box2 );

          TP.Y := 9 ;
          TP.X := 3 ;

          (* Set up box3 and insert it *)

          Box3.Init( TP , 3 , 2 , FALSE , 1 );
          TLD.Insert( Box3 );

          TP.X := TP.X + 10 ;

          (* Set up box and insert it *)

          Box4.Init( TP , 3 , 2 , FALSE , 1 );
          TLD.Insert( Box4 );

          (*   Boxes at  [1] [2]  *)
          (*             [3] [4]  *)

          (* Link Box1 -> Box2 *)
          TDL.Set_Link( @BOX1 , DLink_Right , @BOX2 );

          (* Link Box1 <- Box2 *)
          TDL.Set_Link( @BOX2 , DLink_Left  , @BOX1 );

          (* Link Box3 -> Box4 *)
          TDL.Set_Link( @BOX3 , DLink_Right , @BOX4 );

          (* Link Box3 <- Box4 *)
          TDL.Set_Link( @BOX4 , DLink_Left  , @BOX3 );

          (* Link Box1 -> Box3 *)
          TDL.Set_Link( @BOX1 , DLink_Down  , @BOX3 );

          (* Link Box1 <- Box3 *)
          TDL.Set_Link( @BOX3 , DLink_Up    , @BOX1 );

          (* Link Box2 -> Box4 *)
          TDL.Set_Link( @BOX2 , DLink_Down  , @BOX4 );

          (* Link Box2 <- Box4 *)
          TDL.Set_Link( @BOX4 , DLink_Up    , @BOX2 );

    End;

    }

    { Note:  Tab Size = 4 }

    (* Set conditions to allow for "Extended" type *)
    {$N+,E+}

    (**************************************************************************)
    (*                                                                        *)
    (*               Library of objects for Turbo Vision  V1.00               *)
    (*                                                                        *)
    (*               By:   Devin Cook                                         *)
    (*                     copyright (c) 1990 MSD                             *)
    (*                     Public Domain Object library                       *)
    (*                                                                        *)
    (*   Object:  TDateView                                                   *)
    (*                Same as TClockView, except displays the date            *)
    (*                                                                        *)
    (*   Object:  TPushButton                                                 *)
    (*                Same as TButton, except button "Show" press by keyboard *)
    (*                                                                        *)
    (*   Object:  TNum_Box                                                    *)
    (*                An editable number only entry box - configurable        *)
    (*                                                                        *)
    (*   Object:  TLinked_Dialog                                              *)
    (*                A normal dialog which handles cursor links to other     *)
    (*                items                                                   *)
    (*                                                                        *)
    (*   Func:    FormatDate                                                  *)
    (*                Formats a date into a string                            *)
    (*                                                                        *)
    (**************************************************************************)

    {$F+,O+,S-,D+}

    Interface

    Uses Crt, Dos, Objects, Views, Dialogs, Drivers;

    (*   Constents for Linked_Dialog   *)

    Const        DLink_Left                =        1 ;
                    DLink_Right                =        2 ;
                    DLink_Up                =        3 ;
                    DLink_Down                =        4 ;
                    DLink_Spare1        =        5 ;
                    DLink_Spare2        =        6 ;

    Type

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TDateView                               *)
    (*                                                                        *)
    (*  Desc: TDateView is a static text object of the date, in a formated    *)
    (*        string, usually placed on the status or menu lines.             *)
    (*                                                                        *)
    (*        Format:  Sun  Dec 16, 1990                                      *)
    (*                                                                        *)
    (*        This format can be altered by changing Function FormatDate.     *)
    (*                                                                        *)
    (*  Init: Initialization is done by supply a TRect to the INIT method.    *)
    (*                                                                        *)
    (*  Note: The UPDATE method checks to see if the Day-of-Week value still  *)
    (*        matches the system Day-of-Week, and updates it's view if they   *)
    (*        don't match.  An occasional call to TDateView.UPDATE will keep  *)
    (*        your date indicator up to date.                                 *)
    (*                                                                        *)
    (**************************************************************************)

            PDateView = ^TDateView;
            TDateView = Object(TView)
                                            DateStr: string[19];
                                            Last_DOW: Word;
                                            Constructor Init(var Bounds: TRect);
                                            Procedure Draw; virtual;
                                            Procedure Update; virtual;
                                    End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TPushButton                             *)
    (*                                                                        *)
    (*  Desc: TPushButton is a TButton except that it indicates being         *)
    (*        pressed from the keyboard.                                      *)
    (*                                                                        *)
    (*  Note: You may wish to adjust with the delay values in the             *)
    (*        TPushButton.Press method to suit your taste.                    *)
    (*                                                                        *)
    (*        See TButton for method descriptions.                            *)
    (*                                                                        *)
    (**************************************************************************)

      PPushButton        =        ^TPushButton;
      TPushButton        =        Object(Tbutton)
                                                    Procedure Press ;        Virtual ;
                                            End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TNum_Box                                *)
    (*                                                                        *)
    (*  Desc: TInt_Box is a number only input box with an adjustable number   *)
    (*        of digits before and after the decimal point.                   *)
    (*                                                                        *)
    (*        It can be flagged not to accept negative numbers if desired.    *)
    (*                                                                        *)
    (*  Init: Initialization is done by providing your desired configuration  *)
    (*        to TNum_Box.Init.                                               *)
    (*                                                                        *)
    (*        TNum_Box.Init(                                                  *)
    (*            Loc       -     TPoint with location for num                *)
    (*            MaxWh     -     Integer with #digits before the decimal     *)
    (*                            point                                       *)
    (*            MaxDs     -     Integer with #digits after the decimal      *)
    (*                            point                                       *)
    (*            NegOk     -     Boolean.  True if neg values allowed        *)
    (*            Deflt     -     Extended floating point with default value  *)
    (*                     )                                                  *)
    (*                                                                        *)
    (*  Box width =   MaxWh +                                                 *)
    (*                MaxDs + 1 ( if MaxDs > 0 ) +                            *)
    (*                1 if Negok                                              *)
    (*                                                                        *)
    (*  To read the value back, simply access the Curr_Val variable for the   *)
    (*  TNum_Box.  It is an extended floating point varaible, so you should   *)
    (*  convert it to the desired precision.                                  *)
    (*                                                                        *)
    (*  Note:  A call to TNum_Box.Update_Val "Locks" the edited number into   *)
    (*         the curr_val field, loading the default value if no number has *)
    (*         been entered.                                                  *)
    (*                                                                        *)
    (**************************************************************************)

            PNum_Box    =        ^TNum_Box;
            TNum_Box    =        Object        ( TView )
                                                    Max_Whole        :        Integer ;
                                                    Max_Decs        :        Integer ;
                                                    Max_Len                :        Integer ;
                                                    Neg_Ok      :   Boolean ;
                                                    Default_val        :        Extended ;
                                                    Num_Str                :        String[24] ;
                                                    Curr_Val        :        Extended ;
                                                    Dec_Pos                :        Integer ;
                                                    First_Char        :        Boolean ;

                                                    Constructor Init( Loc        :        TPoint ;
                                                                                      MaxWh :        Integer ;
                                                                                      MaxDs :        Integer ;
                                                                                      NegOk :         Boolean ;
                                                                                      Dflt        :        Extended );
                                                    Procedure Draw;        Virtual;
                                                    Procedure HandleEvent( Var Event:TEvent ); Virtual;
                                                    Procedure SetState( AState:Word; Enable:Boolean);
                                                            Virtual;
                                                    Procedure Add_Digit( Charcode : Char );        Virtual;
                                                    Procedure Do_Edit( Keycode : Word ); Virtual;
                                                    Procedure Update_Value;
                                            End;

    (*  Record used by TLinked_Dialog  *)

                    DLink_Record        =        Record
                                                                    Item                :        Pointer ;
                                                                    Left_Link        :        Pointer ;
                                                                    Right_Link        :        Pointer ;
                                                                    Up_Link                :        Pointer ;
                                                                    Down_Link        :        Pointer ;
                                                                    Spare1_Link        :        Pointer ;
                                                                    Spare2_Link        :        Pointer ;
                                                            End;

    (*  Object for TLinked_Dialog's collection  *)

                    PLink_Item                =        ^TLink_Item ;
                    TLink_Item                =        Object
                                                                    Item                :        Pointer ;
                                                                    Pointers        :        Array[1..6] of Pointer ;
                                                                    Constructor Init( Link_Rec : DLink_Record );
                                                                    Procedure Add_Link( Link_Direc : Integer ;
                                                                                                            Link : Pointer );
                                                            End;

    (*  TLinked_Dialog's collection of links  *)

                    PLinked_List        =        ^TLinked_List ;
                    TLinked_List        =        Object( TCollection )
                                                                    Function Search( key : Pointer ) : Integer ;
                                                            End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TLinked_Dialog                          *)
    (*                                                                        *)
    (*  Desc: TLinked_Dialog is a variation of a standard dialog which        *)
    (*        allows for improved cursor movement between items.              *)
    (*                                                                        *)
    (*        You can define which objects to "Link" to on the right, left,   *)
    (*        above and below.  These objects are focused by use of the       *)
    (*        cursor keys.                                                    *)
    (*                                                                        *)
    (*        Two spare links are defined for item use ( such as switching    *)
    (*        to a certain box once a button is pressed. )                    *)
    (*                                                                        *)
    (*  Init: Initialization is identical to TDialog's init.  Refer to the    *)
    (*        Turbo Vision manual for details.                                *)
    (*                                                                        *)
    (*  Inserting an item is identical to a normal TDialog.Insert. When an    *)
    (*  item is inserted into a TLinked_Dialog, a record is created for       *)
    (*  tracking links.                                                       *)
    (*                                                                        *)
    (*                             Defining a Link                            *)
    (*                                                                        *)
    (*  Once you have inserted all items into your dialog, links are created  *)
    (*  to other items using TLinked_Dialog.Setlink.                          *)
    (*                                                                        *)
    (*  TLinked_Dialog.Setlink(                                               *)
    (*       P          -    PView or descendant.                             *)
    (*                       This is a pointer to the item you wish to add    *)
    (*                       the link to.                                     *)
    (*       Link_Direc -    Integer with link direction.                     *)
    (*                       This should be one of the following constants:   *)
    (*                             DLink_Up     :   Up                        *)
    (*                             DLink_Down   :   Down                      *)
    (*                             DLink_Right  :   Right                     *)
    (*                             DLink_Left   :   Left                      *)
    (*                             DLink_Spare1 :   Spare 1                   *)
    (*                             DLink_Spare2 :   Spare 2                   *)
    (*       Link       -    A pointer to the item you want to link to        *)
    (*       )                                                                *)
    (*                                                                        *)
    (*                           Accesing a link                              *)
    (*                                                                        *)
    (*  Items within a dialog can switch to a linked item by calling:         *)
    (*                                                                        *)
    (*  TLinked_Dialog.Select_link(                                           *)
    (*       Direc      -    Integer with link direction.                     *)
    (*       )                                                                *)
    (*                                                                        *)
    (**************************************************************************)

                    PLinked_Dialog        =   ^TLinked_Dialog ;
                    TLinked_Dialog        =        Object( TDialog )
                                                                    Link_List        :        TLinked_List ;
                                                                    Constructor Init(var Bounds: TRect;
                                                                                                     ATitle: TTitleStr);
                                                                    Procedure Insert(P: PView); Virtual;
                                                                    Procedure Set_Link( P: PView ;
                                                                                                            Link_Direc : Integer ;
                                                                                                            Link : Pointer );
                                                                    Procedure HandleEvent( Var Event : TEvent );
                                                                            Virtual;
                                                                    Procedure Select_Link( Direc : Integer );
                                                            End;

    (**************************************************************************)
    (*                                                                        *)
    (*                      Function: FormatDate                              *)
    (*                                                                        *)
    (*  Desc:  The format date function used by TDateView, made public for    *)
    (*         other possible uses.                                           *)
    (*                                                                        *)
    (**************************************************************************)

    Function FormatDate( Year , Month , Day , DOW : Word ): String;

    Implementation

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TDateView                               *)
    (*                                                                        *)
    (**************************************************************************)

    Constructor TDateView.Init(var Bounds: TRect);
    Begin
            TView.Init(Bounds);
            DateStr := '';
            LAST_DOW := 8 ;     (*  Force an update!  *)
    End;

    (* Draw the TDateView object *)

    Procedure TDateView.Draw;
    Var
            B: TDrawBuffer;
            C: Byte;
    Begin
            C := GetColor(2);
            MoveChar(B, ' ', C, Size.X);
            MoveStr(B, DateStr, C);
            WriteLine(0, 0, Size.X, 1, B);
    End;

    (* Verify the TDateView object is up to date *)
    (* Redisplaying it if it needs updating      *)

    Procedure TDateView.Update;
    Var Year, Month, Day, DOW : word;
    Begin
            GetDate( Year , Month , Day , Dow );
            If (DOW <> LAST_DOW) then
            Begin
                    DateStr := FormatDate( Year , Month , Day , DOW );
                    DrawView;
                    LAST_DOW := DOW ;
            End;
    End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TPushButton                             *)
    (*                                                                        *)
    (**************************************************************************)

    Procedure TPushButton.Press;
    Begin
            DrawState(TRUE);        (*  Draw Button "Pressed"  *)
            Delay(150);
            DrawState(FALSE);        (*  Draw Button "Released" *)
            Delay(50);
            TButton.Press;
    End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TNum_Box                                *)
    (*                                                                        *)
    (**************************************************************************)

    Constructor TNum_Box.Init( Loc : TPoint ; MaxWh, MaxDs : Integer ;
                                                       NegOk : Boolean ;  Dflt : Extended );
    Var        R                :        TRect ;
            X                :        Integer ;
            Wrk_Str :        String ;

    Begin

            Wrk_Str := '' ;
            If ( NegOk ) then
                    Wrk_Str := ' ' ;
            For X := 1 to MaxWh do
                    Wrk_Str := Wrk_Str + ' ' ;

            If ( MaxDs > 0 ) then
            Begin
                    Wrk_Str := Wrk_Str + '.';
                    For X := 1 to MaxDs do
                            Wrk_Str := Wrk_Str + ' ' ;
            End;
            R.Assign( Loc.X , Loc.Y , Loc.X + Length( Wrk_Str ) , Loc.Y + 1 );
            TView.Init( R ) ;

            Num_Str := Wrk_Str ;

            Neg_Ok := NegOk ;
            Max_Whole := MaxWh ;
            Max_Decs := MaxDs ;

            Max_Len := Length( Num_Str );

            Options := Options OR ofSelectable ;

            Default_Val := Dflt ;
            Curr_Val := Dflt ;
            Dec_Pos := Pos( '.' , Num_Str );

            If ( Dec_Pos < 1 ) then
                    Dec_Pos := Max_Len + 1 ;

            Cursor.X := Dec_Pos - 2;

            First_Char := True ;
            ShowCursor;
    End;

    (*  Draw the TNum_Box on the view.  *)
    (*  Color depends on the state of   *)
    (*  the object.                     *)

    Procedure TNum_Box.Draw;
    Var        Buff : TDrawBuffer ;
            Colr : Word;
    Begin
            Colr := GetColor(19);
            If GetState(sfFocused) then
                    If First_Char then
                            Colr := GetColor(20)
                    else
                            Colr := GetColor(22);

            MoveChar( Buff,' ',Colr, Size.X);
            MoveStr( Buff,Num_Str,0);
            Writeline(0,0,Size.X,1,Buff);

    End;

    (*  Updated SetState to watch for changes in the  *)
    (*  selected and focused flags.                   *)

    Procedure TNum_Box.SetState(AState: Word; Enable: Boolean);
    Begin
            TView.SetState(AState, Enable);
            If ( AState = sfFocused ) then
                    Draw ;
            If ( AState = sfFocused ) And ( Enable ) then
                    First_Char := TRUE ;
    End;

    (*  HandleEvent, routing keystrokes  *)

    Procedure TNum_Box.HandleEvent( Var Event : TEvent );
    Var        NextCmd: TEvent;
            test:PEvent;
    Begin
            TView.HandleEvent( Event );
            If Event.What = evKeydown then
            Begin
                    Case ( Event.Charcode ) of
                            #00                :   Begin
                                                    End;
                            #08                :        Begin
                                                            Do_Edit( Event.keyCode );
                                                            ClearEvent( Event );
                                                    End;
                            #13                :        Begin
                                                            ClearEvent( Event );
                                                            Update_Value ;
                                                    End;
                            '0'..'9':        Begin
                                                            Add_Digit( Event.Charcode );
                                                            ClearEvent( Event );
                                                    End;
                            '.','-':        Begin
                                                            Add_Digit( Event.Charcode );
                                                            ClearEvent( Event );
                                                    End;
                            End;
            End;
    End;

    (*  Perform normal charector addition to the number string  *)

    Procedure TNum_Box.Add_Digit( Charcode : Char );
    Var        X                        :        Integer ;
            First_Dig        :        Integer ;
    Begin

            If ( First_Char ) then
            Begin
                    For X := 1 to Length( Num_Str ) do
                            If (Num_Str[X]<>'.') then
                                    Num_Str[X]:=' ';

                    First_Char := False ;
                    Cursor.X := Dec_Pos - 2;
                    ShowCursor;
            End;

            If Neg_Ok then
                    First_Dig := 2
            else
                    First_Dig := 1;

            If ( Cursor.X < Dec_Pos ) then
            Case ( Charcode ) of
                    '0'..'9'        :        If Not( Num_Str[ First_Dig ] IN ['0'..'9']) then
                                                    Begin
                                                            For X := 1 to Cursor.X do
                                                                    Num_Str[X] := Num_Str[X+1] ;
                                                            Num_Str[ Cursor.X + 1 ] := Charcode ;
                                                    End;
                    '-'                        :        Begin
                                                            If (Neg_Ok) then
                                                            Begin
                                                                    if (Num_Str[ Cursor.X + 1 ] = ' ') then
                                                                            Num_Str[ Cursor.X + 1 ] := '-'
                                                            End;
                                                    End;
                    '.'                        :        Begin
                                                            If (Max_Decs>0) and ( Cursor.X < Dec_Pos ) then
                                                            Begin
                                                                    Cursor.X := Dec_Pos ;
                                                                    ShowCursor;
                                                            End;
                                                    End;
            End
            else
            Case ( Charcode ) of
                    '0'..'9'        :        Begin
                                                            If ( Cursor.X < ( Max_Len - 1 )) then
                                                            Begin
                                                                    Num_Str[Cursor.X+1] := Charcode ;
                                                                    Inc( Cursor.X );
                                                                    ShowCursor;
                                                            End
                                                            else
                                                                    if Num_Str[Cursor.X+1] = ' ' then
                                                                            Num_Str[Cursor.X+1] := Charcode ;
                                                    End;
            End;

            Draw;
    End;

    (*  Perform any editing on the number string  *)
    (*  ( Only the <Backspace> key is currently   *)
    (*  supported ).                              *)

    Procedure TNum_Box.Do_Edit( Keycode : Word );
    Var        X                        :        Integer ;
    Begin
            First_Char := False ;
            If ( Dec_Pos = 0 ) or ( Cursor.X < Dec_Pos ) then
            Begin
                    If (Keycode = kbBack) then
                    Begin
                            For X := Cursor.X+1 downto 2 do
                                    Num_Str[X] := Num_Str[X-1] ;
                            Num_Str[ 1 ] := ' ' ;
                    End;
            End
            else
            Begin
                    If (Keycode = kbBack) then
                    Begin
                            If Num_Str[Cursor.X+1] = ' ' then
                            Begin
                                    Dec( Cursor.X );
                                    Num_Str[Cursor.X+1] := ' ';
                            End
                            else
                                    Num_Str[Cursor.X+1] := ' ';

                            If Num_Str[ Cursor.X ] = '.' then
                                    Cursor.X := Cursor.X - 2 ;
                            ShowCursor;
                    End;
            End;

            Draw;
    End;

    (* "Lock" the number string value in the box.     *)
    (* Use the default value if no number is present. *)

    Procedure TNum_Box.Update_Value;
    Var Code        :        Integer ;
            Work_str:        String[24];
    Begin
            Work_Str := Num_Str ;
            While (( Length( Work_Str )>0 ) and ( Work_Str[Length( Work_Str )] IN ['.',' '])) do
                    Work_Str := Copy( Work_Str , 1 , length( Work_Str ) -1 );

            Code := 0 ;

            If ( Work_Str = '' ) then
                    Curr_Val := Default_Val
            else
                    Val( Work_Str, Curr_Val , Code );
            Str( Curr_Val:Max_Len:Max_Decs , Num_Str );

            Cursor.X := Max_Len - 1 ;
            First_Char := True ;
            Draw;
    End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TLink_Item                              *)
    (*                                                                        *)
    (*                 Used by TLinked_Dialog to track links                  *)
    (*                                                                        *)
    (**************************************************************************)

    Constructor TLink_Item.Init( Link_Rec : DLink_Record );
    Begin
            Item := Link_Rec.Item ;
            With Link_Rec do
            Begin
                    Pointers[DLink_Left]        := Left_Link;
                    Pointers[DLink_Right]        := Right_Link;
                    Pointers[DLink_Up]                := Up_Link;
                    Pointers[DLink_Down]         := Down_Link;
                    Pointers[DLink_Spare1]        := Spare1_Link;
                    Pointers[DLink_Spare2]        := Spare2_Link;
            End;
    End;

    Procedure TLink_Item.Add_Link( Link_Direc : Integer ; Link : Pointer );
    Begin
            Pointers[ Link_Direc ] := Link ;
    End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TLink_List                              *)
    (*                                                                        *)
    (*                 Used by TLinked_Dialog to track links                  *)
    (*                                                                        *)
    (**************************************************************************)

    Function TLinked_List.Search( Key : Pointer ) : Integer ;
    Var        X : Integer ;
            Found : Boolean ;
            Linked_Item : PLink_Item ;
    Begin
            Search := -1 ;
            Found := False ;
            X := 0 ;
            While ( X < Count ) AND ( NOT FOUND ) do
            Begin
                    Linked_Item := at( X );
                    Found := Linked_Item^.Item = Key ;
                    X := X + 1 ;
            End;

            If ( Found ) then
                    Search := X - 1 ;
    End;

    (**************************************************************************)
    (*                                                                        *)
    (*                        Object: TLinked_Dialog                          *)
    (*                                                                        *)
    (**************************************************************************)

    Constructor TLinked_Dialog.Init(var Bounds: TRect; ATitle: TTitleStr);
    Begin
            TDialog.Init( Bounds , ATitle );
            Link_List.Init(10, 5);
    End;

    Procedure TLinked_Dialog.Insert(P: PView);
    Var        Linked_Item : PLink_Item ;
            Blank_Rec : DLink_Record ;
    Begin
            With Blank_Rec do
            Begin
                    Item := P ;
                    Left_Link         := Nil ;
                    Right_Link        := Nil ;
                    Up_Link                := Nil ;
                    Down_Link        := Nil ;
                    Spare1_Link        := Nil ;
                    Spare2_Link := Nil ;
            End;
            Linked_Item := New( PLink_Item , Init( Blank_Rec ) );
            TDialog.Insert( P );
            Link_List.Insert( Linked_Item );
    End;

    Procedure TLinked_Dialog.Set_Link(P:PView;Link_Direc:Integer;Link:Pointer);
    Var        Linked_Item : PLink_Item ;
            X : Integer ;
    Begin
            X := Link_List.Search( P );
            If ( X < 0 ) then
                    Exit ;
            Linked_Item := Link_List.at( X );
            Linked_Item^.Pointers[ Link_Direc ] := Link ;
    End;

    Procedure TLinked_Dialog.Select_Link( Direc : Integer );
    Var        X                : Integer ;
            LL_Item        : PLink_Item ;
            Item        : PView ;
    Begin
            X := Link_List.Search( Current );
            LL_Item := Link_List.at(X);
            Item := LL_Item^.Pointers[ Direc ];
            If ( Item <> Nil ) then
                    Item^.Select ;
    End;

    Procedure TLinked_Dialog.HandleEvent( Var Event : TEvent );
    Var        X                : Integer ;
            LL_Item        : PLink_Item ;
            Item        : PView ;
    Begin
            TDialog.HandleEvent( Event );

            If ( Event.What = evKeydown ) then
                    Case Event.keycode of
                            kbUp        :        Begin
                                                            Select_Link( DLink_Up );
                                                            ClearEvent( Event );
                                                    End;
                            kbDown        :        Begin
                                                            Select_Link( DLink_Down );
                                                            ClearEvent( Event );
                                                    End;
                            kbRight        :        Begin
                                                            Select_Link( DLink_Right );
                                                            ClearEvent( Event );
                                                    End;
                            kbLeft        :        Begin
                                                            Select_Link( DLink_Left );
                                                            ClearEvent( Event );
                                                    End;
                    End;
    End;

    (**************************************************************************)
    (*                                                                        *)
    (*                      Function: FormatDate                              *)
    (*                                                                        *)
    (**************************************************************************)

    Function FormatDate( Year , Month , Day , DOW : Word ): String;
    Const
            DAYS : Array[0..6] of String = ( 'Sun','Mon','Tue','Wed','Thu','Fri','Sat');
            MONTHS : Array[1..12] of String = ( 'Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
    Var Work1,Work2 : String[4] ;
    Begin
            Str( Day,Work1 );
            If ( Day < 10 ) then
            Work1 := '0' + Work1 ;
            Str( Year,Work2 );
            FormatDate := DAYS[DOW]+'  '+MONTHS[Month]+' '+Work1+', '+Work2;
    End;

    Begin
    end.

    {-----------------------    DEMO CODE --------------------- }

    Program Example;

    Uses Crt,App, Objects, Views, Dialogs, Drivers, Misc;

    Type
            PMyApp                =        ^TMyApp ;
            TMyApp                =        Object( TApplication )
                                                    Constructor Init;
                                            End;

    Var
            MyApp        :        TMyApp ;
            Dialog  :   PLinked_Dialog;

            Screen_Array        :        Array[1..70] of TNum_Box;

    Procedure Build_Links;
    Var        P        :        TPoint ;
            X,Y :        Integer ;
            N        :        Integer ;
    Begin

            For N := 1 to 50 do
            Begin
                    P.Y := ( N - 1 ) DIV 10         + 8 ;
                    P.X := ( N - 1 ) MOD 10 * 4 + 20 ;

                    Screen_Array[N].Init( P , 3 , 0 , FALSE , N );
                    Screen_Array[N].Update_Value;
            End;

            For N := 1 to 8 do
            Begin
                    P.Y := ( N - 1 ) Div 3 * 2 + 8  ;
                    P.X := ( N - 1 ) Mod 3 * 4 + 60 ;
                    If ( N > 6 ) then
                            P.X := P.X + 4 ;
                    Screen_Array[N+50].Init( P , 3 , 0 , FALSE , N+50 );
                    Screen_Array[N+50].Update_Value;
            End;

            P.Y := 6 ;

    (* Initialize 5 floating point boxes *)

            For N := 1 to 5 do
            Begin
                    P.X := ( N * 12 ) ;
                    Screen_Array[N+58].Init( P , 4 , 2 , True , N+58 );
            End;

    (* Insert all boxes before setting links! *)

            For N := 1 to 63 do
                    Dialog^.Insert( @Screen_Array[N] );

            For N := 1 to 50 do
            Begin
                    if ( N MOD 10 ) <> 1 then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Left ,@Screen_array[N-1]);
                    if ( N MOD 10 ) <> 0 then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Right,@Screen_array[N+1]);
                    if ( N > 10 ) then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Up   ,@Screen_array[N-10])
                    else
                            Dialog^.Set_Link(@Screen_array[N],DLink_Up   ,@Screen_array[59]);

                    if ( N <41 ) then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Down ,@Screen_array[N+10]);

                    if ( N=10 ) or ( N=20 ) then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Right,@Screen_array[51]);

                    if ( N=30 ) or ( N=40 ) then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Right,@Screen_array[54]);
            End;

            Dialog^.Set_Link(@Screen_array[50],DLink_Right,@Screen_array[57]);

            Dialog^.Set_Link(@Screen_array[51],DLink_Left ,@Screen_array[10]);
            Dialog^.Set_Link(@Screen_array[51],DLink_Right,@Screen_array[52]);
            Dialog^.Set_Link(@Screen_array[51],DLink_Down ,@Screen_array[54]);

            Dialog^.Set_Link(@Screen_array[52],DLink_Left ,@Screen_array[51]);
            Dialog^.Set_Link(@Screen_array[52],DLink_Right,@Screen_array[53]);
            Dialog^.Set_Link(@Screen_array[52],DLink_Down ,@Screen_array[55]);

            Dialog^.Set_Link(@Screen_array[53],DLink_Left ,@Screen_array[52]);
            Dialog^.Set_Link(@Screen_array[53],DLink_Down ,@Screen_array[56]);

            Dialog^.Set_Link(@Screen_array[54],DLink_Left ,@Screen_array[30]);
            Dialog^.Set_Link(@Screen_array[54],DLink_Right,@Screen_array[55]);
            Dialog^.Set_Link(@Screen_array[54],DLink_Down ,@Screen_array[57]);
            Dialog^.Set_Link(@Screen_array[54],DLink_Up   ,@Screen_array[51]);

            Dialog^.Set_Link(@Screen_array[55],DLink_Left ,@Screen_array[54]);
            Dialog^.Set_Link(@Screen_array[55],DLink_Right,@Screen_array[56]);
            Dialog^.Set_Link(@Screen_array[55],DLink_Down ,@Screen_array[57]);
            Dialog^.Set_Link(@Screen_array[55],DLink_Up   ,@Screen_array[52]);

            Dialog^.Set_Link(@Screen_array[56],DLink_Left ,@Screen_array[55]);
            Dialog^.Set_Link(@Screen_array[56],DLink_Down ,@Screen_array[58]);
            Dialog^.Set_Link(@Screen_array[56],DLink_Up   ,@Screen_array[53]);

            Dialog^.Set_Link(@Screen_array[57],DLink_Left ,@Screen_array[50]);
            Dialog^.Set_Link(@Screen_array[57],DLink_Right,@Screen_array[58]);
            Dialog^.Set_Link(@Screen_array[57],DLink_Up   ,@Screen_array[55]);

            Dialog^.Set_Link(@Screen_array[58],DLink_Left ,@Screen_array[57]);
            Dialog^.Set_Link(@Screen_array[58],DLink_Up   ,@Screen_array[56]);

            For N := 59 to 63 do
            Begin
                    if ( N > 59 ) then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Left ,@Screen_array[N-1]);
                    if ( N < 63 ) then
                            Dialog^.Set_Link(@Screen_array[N],DLink_Right,@Screen_array[N+1]);
                    Dialog^.Set_Link(@Screen_array[N],DLink_Down,@Screen_array[1]);
            End;
    End;

    Procedure Do_Dialog;
    Var        R                :        TRect ;
            TP                :        TPoint ;
            N                :        Integer ;
            Button        :        PButton ;
    Begin

            R.Assign( 0 , 10 , 80 , 24 );
            Dialog := New( PLinked_Dialog , Init( R , 'Linked Dialog Example' ));
            Dialog^.SetState(sfShadow,False );

            Build_Links;

            R.Assign( 5 , 8 , 15 , 10 );
            Button := New(PPushButton,Init(R,'~P~ush',cmOk,bfDefault));
            Dialog^.Insert( Button );

            R.Assign( 5 , 11 , 15 , 13 );
            Button := New(PPushButton,Init(R,'~E~xit',cmQuit,bfDefault));
            Dialog^.Insert( Button );

            Dialog^.Set_Link(Button,DLink_Right,@Screen_array[1]);

            MyApp.Insert( Dialog );

    End;

    Constructor TMyApp.Init;
    Begin
            TApplication.Init ;
            Do_Dialog;
    End;

    Begin
            ClrScr;
            MyApp.Init ;
            MyApp.Run ;
            MyApp.Done ;
    End.

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