Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!samsung!zaphod!wuarchive!uunet!infonode!ingr!b17b!shaman!wolf
From: wolf@shaman.ingr.com (Wayne Wolf)
Newsgroups: comp.lang.pascal
Subject: Re: Queueing multiple events in a Turbo Vision application
Keywords: Turbo Vision, Pascal, Events, Queue
Message-ID: <638@b17b.INGR.COM>
Date: 15 Jan 91 18:10:01 GMT
References: <637@b17b.INGR.COM>
Sender: usenet@b17b.INGR.COM
Reply-To: ...!uunet!ingr!wyle!shaman!wolf
Organization: Intergraph Corporation
Lines: 161


Yesterday I posted to this group, a query for some help in designing 
functionality into a Turbo Vision application to allow inserting multiple
events into the event queue.  I did not receive any response, but I did find
the solution after paging through the manual with more intensity.  There is
only a minor reference on how to accomplish this feat on page 125 under
heading "Overriding GetEvent."  I will include the source code I came up
with to perform this event queue.  The utility varies from implementing
keyboard macros, to automating your application by reading a stream of
commands and placing them into the event queue, to having one event cause
a chain of multile events to occur.  The code was written in about 30 mins
and tested briefly, but appears to work.  Any commentary is appreciated.
I hope this will help anyone else who wants to implement this sort of
functionality.  Following are the new class definition you should inherit
your application from, and then a sample program excerpt to show how the
new class and its methods are used.  Any usage questions, please send email
to either of ...!uunet!ingr!wyle!shaman!wolf or ww@beach.cis.ufl.edu.

---  Cut HERE -------

Unit AutoApp;
{$F+,O+}        (* Force far calls, allow overlaying *)

Interface

Uses
   App,
   Drivers;

Const
   MaxEventQueue = 50;
   NullEvent : TEvent = (What:evNothing);

Type
   EventQueueType = array[1..MaxEventQueue] of TEvent;

   PAutoApplication = ^TAutoApplication;
   TAutoApplication = object(TApplication)
      EventQueue : EventQueueType;
      QueueHead : word;
      QueueTail : word;

      Constructor Init;

      function    EventInQueue: boolean;
      procedure   GetEvent(var Event: TEvent); virtual;
      procedure   GetNextEventFromQueue(var Event: TEvent);
      procedure   InitEventQueue;
      procedure   PutEventIntoQueue(NewEvent: TEvent);
   End; {TAutoApplication}

Implementation

(*---------------------------------------------------------------------------*)
(*         M E T H O D S :  TAutoApplication                                 *)
(*---------------------------------------------------------------------------*)

   Constructor TAutoApplication.Init;
   Begin
      TApplication.Init;
      InitEventQueue;
   End;

(*---------------------------------------------------------------------------*)

   Function TAutoApplication.EventInQueue: boolean;
   Begin
      EventInQueue := QueueHead <> QueueTail;
   End;

(*---------------------------------------------------------------------------*)

   Procedure TAutoApplication.GetEvent(var Event: TEvent);
   Begin
      if EventInQueue then
         GetNextEventFromQueue(Event)
      else
         TApplication.GetEvent(Event);
   End;

(*---------------------------------------------------------------------------*)

   Procedure TAutoApplication.GetNextEventFromQueue(var Event: TEvent);
   Begin
      Event := EventQueue[QueueHead];
      EventQueue[QueueHead] := NullEvent;
      if QueueHead = MaxEventQueue then
         QueueHead := 1
      else
         inc(QueueHead);
   End;

(*---------------------------------------------------------------------------*)

   Procedure TAutoApplication.InitEventQueue;
   Var
      i : word;
   Begin
      QueueHead := 1;
      QueueTail := 1;
      for i := 1 to MaxEventQueue do 
         EventQueue[i] := NullEvent;
   End;

(*---------------------------------------------------------------------------*)

   Procedure TAutoApplication.PutEventIntoQueue(NewEvent: TEvent);
   Begin
      EventQueue[QueueTail] := NewEvent;
      if QueueTail = MaxEventQueue then
         QueueTail := 1
      else
         inc(QueueTail);
   End;

(*---------------------------------------------------------------------------*)

END.


-----------

To implement this new functionailty, your application object will inherit
from TAutoApplication, instead of TApplication.  Then, you could have
a procedure to perform a series of events.  For example, say the events
to open a file called foo.pas were an OpenFile command, and then the keypresses
for 'foo.pas'.  The following procedure would implement this automatically.
Note, the kb_xxx constants you will have defined somewhere within scope.

Procedure MyApplication.AutoOpenFoo;
   Const
      NumEvents = 9;
      AutoEvents: array[1..NumEvents] of TEvent = (
         (What:evCommand; Command: cmOpenFile),
         (What:evKeyDown; KeyCode: kb_f),
         (What:evKeyDown; KeyCode: kb_o),
         (What:evKeyDown; KeyCode: kb_o),
         (What:evKeyDown; KeyCode: kb_dot),
         (What:evKeyDown; KeyCode: kb_p),
         (What:evKeyDown; KeyCode: kb_a),
         (What:evKeyDown; KeyCode: kb_s),
         (What:evKeyDown; KeyCode: kbEnter),
      );

   Var
      i : word;
   Begin
      for i := 1 to NumEvents do
         PutEventIntoQueue(AutoEvents[i]);
   End;

-----------

If anyone has some $0.02 to add please do.

..

Wayne Wolf

USENET  : ...!uunet!ingr!wyle!shaman!wolf  (try this one first)
Internet: ww@beach.cis.ufl.edu             (forwards to shaman!wolf)