NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/comp/lang/pascal/7732

Text File | 1992-12-30 | 4.7 KB | 141 lines

Newsgroups: comp.lang.pascal
Path: sparky!uunet!munnari.oz.au!spool.mu.edu!yale.edu!qt.cs.utexas.edu!cs.utexas.edu!usc!howland.reston.ans.net!paladin.american.edu!gatech!concert!rock!taco!csemail.cropsci.ncsu.edu!samodena
From: [e-mail] (S. A. Modena)
Subject: Re: BP7 and Turbovision Questions
Message-ID: <[e-mail]>
Summary: Event-driven programming is speak-easy
Sender: [e-mail] (USENET News System)
Organization: Crop Science Dept., NCSU, Raleigh, NC 27695-7620
References: <[e-mail]>
Date: Wed, 30 Dec 1992 14:42:42 GMT
Lines: 128

In article <[e-mail]> [e-mail] (Kristen Anne Pribis) writes:
>The last time I programmed in Pascal I used TP 4.0.  I recently
>received BP 7.0 and am absolutely amazed at its capabilities.
>I am slowly working my way through Turbo Vision, and have a
>question.  I would like a data entry window to be opened as
>soon as the program starts, asking for the user to swipe a
>credit card through a card reader (simulates keyboard input).
>If the card is swiped through (the string ends with '?'), I
>want to run a routine without the user having to hit enter or
>any key.  If the user presses F3, instead of swiping the card,
>I would like to run another routine for manual entry.
>
>1) Where should I place the first window procedure?  In the
>Application Init constructor?  Or can I simulate an event and
>pass the simulated event (such as cmOpenInitWindow or
>something) to the HandleEvent procedure?

The last few lines of MyApp.Init should be something like:

CONSTRUCTOR MyApp.Init;
    BEGIN
        ....
        INHERITED Init;
    .......
    NextEvent.What := evCommand;
    NextEvent.Command := cmRunCreditCardEntryRoutine;
    NextEvent.InfoPtr := @SELF;
    INHERITED PutEvent( NextEvent );
    END;

This will be handled by:
    PROCEDURE MyApp.HandleEvent();
        BEGIN
                ..........
        cmRunCreditCardEntryRoutine:
            BEGIN
            SELF.RunCreditCardEntryRoutine;
            INHERITED ClearEvent( Event );
            END;
                cmRunTheManualEntryInputRoutineInstead:
                BEGIN
            SELF.RunTheManualEntryInpurRoutineInstead;
            INHERITED ClearEvent( Event );
            END;
                 .....
                INHERITED HandleEvent( event );
        END;

PROCEDURE MyApp.RunCreditCardEntryRoutine;
    BEGIN
    ....gory setup details....
    Result := DeskTop^.ExecView( MyCreditCardInputLineDialogP );
    IF ( Result <> cmCancel )
       THEN CASE Result OF
             cmOk: BEGIN
               ...gory details for credit card swipe....
               END;
                 cmRunTheManualInputRoutineInstead:
            BEGIN
                NextEvent.What := evCommand;
            NextEvent.Command := Result;
            NextEvent.InfoPtr := @SELF;
            INHERITED PutEvent( NextEvent );
            END;
        END;
    END;

>
>2) How can I scan a data entry field for a '?' and then end data
>entry once it receives the '?'?

One way to do it:

PROCEDURE MyCeditCardInputLineDialog.HandleEvent()
    BEGIN
    ....
    IF (( Event.What AND evKeyDown ) <> 0 )
       BEGIN
       CASE Event.KeyCode OF
        kbQuestionMark: Event.KeyCode := kbTab;
                kbF3: BEGIN
              INHERITED EndModal( cmRunTheManualInputRoutineInstead );
              INHERITED ClearEvent( Event );
              END;
        END;
       END;
        INHERITED HandleEvent( Event );
    END;

>
>3) If I'm scanning for a '?', can I still capture an F3 to run a
>different routing?

See above for details intertwined...

>
>The following is an example of a credit card swipe, but imagine
>it all on a single line:
>
>%B5123456789012345^SMITH/JOE^951110112102OP/0000000000000000?
>
>The ^9511 is the expiration date - 11/95.  The first string of
>numbers is the credit card number.
>
>Any sample code would be greatly appreciated.
>Replies can be posted here, but preferably mailed to me at
>[e-mail].  Thanks in advance, and to all of those who
>helped me with my async communications questions.

This is an outline just off the top of my head.....which in event
driven programming comes out being structured quite close to the
way you expressed the problem.  :^)

I'll leave the implementation details to you.  :^)

Steve
---
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|     In person:  Steve Modena     AB4EL                           |
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