How to transform TurboBasic to PBCC ??

[Aimo Niemi]

Hi
Sorry to bother you with an old question but I am a new user of PBCC and would like to know what it can do and what not.
In my old TurboBasic code I frequntly used ON KEY(n) GOSUB statements to do various things, regardless where the program was actually running, when the KEYn was pressed. In the old good days Turbos compiler put an event trapping test after each sentence of the code to do that but, what about PBCC? Is that still possible with some clever trick, which I have not yet succeeded to find?

[Michael Mattias]

Interesting... in the "upgrading from DOS" section of the PB/CC 5.0.2 help file, "Keyword Differences" section, there is no mention at all of the "ON xxxxx" statements at all. (Although other obsolete language elements such as BLOAD/BSAVE, CLEAR, DEF SEG, INP/OUT/WAIT, etc are included in that section.)

However, were that clearly overlooked entry included as it should have been, it would simply tell you "not supported."

The bottom line is, you will have to query the keystrokes yourself (WAITKEY$ is good) and 'do something' when a "key of interest" has been received. Sorry, there are no "clever tricks" available.

MCM

[Manuel Valdes]

Aimo:

As far as I remember, On Key(n) statement doesn't work alone, but nested in a pair of Key On/ Key Off statements. That can be replaced in PBCC with Waitkey$ or Inkey$ nested in a Do/ Loop pair with an exit granted by a key being pressed. I think you can find a lot of examples of this in the PBCC forum.

Best regards,

[Mel Bishop]

...(WAITKEY$ is good)...there are no "clever tricks" available...

WAITKEY$ is okay if you want to stall the rest of your program while it's waiting for a keystroke.

"no clever tricks"? Not quite. Selecting INKEY$ checks the keyboard buffer and keeps on trucking. If there's something there, okay. If not, well, that's okay as well.

The only thing is that you have to INKEY$ at each point you would like the program to jump to when that key is pressed.

Added: Also, Aimo, in CC you cannot GOSUB to a routine outside the confines of the function you are in. You have to put the sub routine in the function calling it or change it to a SUB or FUNCTION.

[Michael Mattias]

WAITKEY$ is okay if you want to stall the rest of your program while it's waiting for a keystroke.

I acknowledge I don't do much with the Console Compiler, but wouldn't a console application looking for "F5" normally be in some kind of "wait for keystroke" state anyway?

I suppose you could say you want this to work the MS-DOS worked, where after each statement the keyboard buffer was checked and if a magic key were found the program would branch to the nominated subroutine.

BUt since the compiler is not inserting those event checks, you'd have to do it yourself. I suppose you could use a MACRO to pull it off...

 
MACRO FUNCTION CheckForKey 
 MACROTEMP X
 DIM X AS STRING 
   X = INKEY$ 
   IF X$ = F3 
      GOSUB  F3_Key 
   ELSEIF X$ = F5 THEN 
      GOSUB F5_Key
   ....
END MACRO 

FUNCTION Something 
.....
   Statement 
   CheckForKey
   Statement 
   checkforkey 

   ...
    EXIT FUNCTION 

F3_Key:
 stuff
RETURN 

F5_Key: 
  stuff
RETURN

END FUNCTION

It's a thought....

MCM

[Mel Bishop]

...a console application looking for "F5" normally be in some kind of "wait for keystroke" state anyway?

It can be, but not necessairly. In TB/PB/DOS, on key(x) gosub y keeps the program moving until the appropriate key is pressed. Then it jumps to whereever.

Consider:

function pbmain()
do
an$ = inkey$
if an$ = chr$(27) then exit loop          'ESCape key pressed. Abort
if an$ = F3 then gosub DoSomething
'other traps here
loop

exit function

DoSomething:
...process
...process
return


end function

I think this would be the appropriate way to go.

I used to have all the function key codes close at hand but not any more. It's easy enough to write a small utility to get these codes anyway.

[Chris Holbrook]

If you got your keystrokes from a subclassed GRAPHIC WINDOW (for example) then you could build a function/sub address array in a way analogous to ON KEY GOSUB and call them from the subclass function irrespective of the main loop logic.

[Manuel Valdes]

After some 20 years I was re-reading the Turbo Basic Owner's Handbook, and think maybe the code below is more connected to the specific need.

 
#COMPILE EXE
 
FUNCTION PBMAIN() AS LONG
CURSOR OFF
DO
 DO UNTIL INSTAT
  SLEEP 1  'Reduce the CPU Usage demand
 LOOP
 O$=UCASE$(INKEY$)
 IF O$=CHR$(27) THEN EXIT LOOP
 SELECT CASE O$
  CASE CHR$(0,59)'F1
   PRINT "Pressed Function Key F1"
   'Gosub Something/Call Something
  CASE CHR$(0,60)'F2
   PRINT "Pressed Function Key F2"
  CASE CHR$(0,61)'F3
   PRINT "Pressed Function Key F3"
  CASE CHR$(0,62)'F4
   PRINT "Pressed Function Key F4"
  CASE CHR$(0,63)'F5
   PRINT "Pressed Function Key F5"
  CASE CHR$(0,64)'F6
   PRINT "Pressed Function Key F6"
  CASE CHR$(0,65)'F7
   PRINT "Pressed Function Key F7"
  CASE CHR$(0,66)'F8
   PRINT "Pressed Function Key F8"
  CASE CHR$(0,67)'F9
   PRINT "Pressed Function Key F9"
  CASE CHR$(0,68)'F10
   PRINT "Pressed Function Key F10"
  CASE CHR$(0,71)'Home
   PRINT "Pressed Home Key"
  CASE CHR$(0,72)'AUp
   PRINT "Pressed Arrow Up Key"
  CASE CHR$(0,73) 'PUp
   PRINT "Pressed Page Up Key"
  CASE CHR$(0,75) 'Left
   PRINT "Pressed Left Arrow Key"
  CASE CHR$(0,77) 'Right
   PRINT "Pressed Right Arrow Key"
  CASE CHR$(0,79) 'End
   PRINT "Pressed End Key"
  CASE CHR$(0,80) 'ADown
   PRINT "Pressed Arrow Down Key"
  CASE CHR$(0,81) 'PDown
   PRINT "Pressed Page Down Key"
  CASE CHR$(0,82) 'Ins
   PRINT "Pressed Insert Key"
  CASE CHR$(0,83) 'Del
   PRINT "Pressed Delete Key"
  END SELECT
LOOP
END FUNCTION

[Aimo Niemi]

Aimo thanks all of you

If you got your keystrokes from a subclassed GRAPHIC WINDOW (for example) then you could build a function/sub address array in a way analogous to ON KEY GOSUB and call them from the subclass function irrespective of the main loop logic.

Thank you Chris. I will try to understand this. Meanwhile, I think, I must use INKEY$ and create my own event handling routine. And then, of course, I must try to find right places, where to put this routine so that it works as intended.
My difficulty lies in that I have written a calculator program (PcCalculator) where the user can create his own program loops and, if now his (or her) loop is too slow or if he accidentally creates a never-ending loop, then there must be some way to get rid of it. So, I must try to find all possible routes, where the user loop may visit and put then my event trapping routine there.

[Chris Holbrook]

This code should carry a health warning, as there are limits to what you can do with subclassing and GRAPHIC WINDOWS. But is does more or less answer Aimo's question, which included the words "clever trick"!

' to demonstrate ONKEY behaviour using a subclassed graphic window
#compile exe
#debug display
#include "WIN32API.INC"
%KEY_ESC     = 27

global hGW as dword
global GrDialogProc as long
global GrStaticProc as long
global ghstatic as dword
type tONKEY
    key as long
    procptr as dword
end type
global gONKEY() as tONKEY

declare sub proto()
'-------------------------------------------------------------------------------
function GrProc(byval hWnd as dword, byval wMsg as dword, byval wParam as dword, byval lParam as long) as long
  local s as string
  local i as long

  select case wMsg
    case %wm_char                          ' here we catch keys
        s = "SUBCLASS PROC DETECTS <" + chr$(wparam) + ">"
        sendmessage getparent(hWnd), %WM_SETTEXT, 0, strptr(s)
        for i = lbound(gONKEY()) to ubound(gONKEY())
            if gONKEY(i).key = wparam then
                call dword gONKEY(i).procptr using proto()
                exit for
            end if
        next
  end select

  function = CallWindowProc(GrStaticProc, hWnd, wMsg, wParam, lParam)

end function
'=============================================
'=============================================
' OUR ONKEY SUBS - could be functions
' but either way all must have the same type and params
'=============================================
'---------------------------------------------
sub procA
    ? "IN PROC A"
    graphic attach hGW, 0
    graphic clear %cyan
end sub
'---------------------------------------------
sub procB
    ? "IN PROC B"
    graphic clear %red
end sub

function pbmain () as long
    local r as rect
    local qtc as quad
    local s, skey as string

    graphic window "ONKEY TEST", 100, 100, 450, 450 to hGW
    '=========================================
    ' START THE SUBCLASSING
    '=========================================
    ' Retrieve static handle of graphic window
    ghStatic = GetWindow(hGW, %GW_CHILD)
    ' Subclasses Graphic control
    GrStaticProc = SetWindowLong(ghStatic, %GWL_WNDPROC, codeptr(GrProc))
    '=========================================
    graphic attach hGW, 0
    graphic color %black, %white
    graphic set pos ( 20, 340)
    graphic print "ESC to exit"
    '=========================================
    ' LOAD UP THE ONKEY array - you can wrap this up in a function
    '=========================================
    dim gONKEY(0 to 1 ) as global tONKEY
    gONKEY(0).key = asc("A"): gONKEY(0).procptr = codeptr(procA)
    gONKEY(1).key = asc("B"): gONKEY(1).procptr = codeptr(procB)
    '=========================================
    ' MAIN PROGRAM LOOP - THIS ONE IS RATHER SIMPLE
    '=========================================
    do
        graphic ellipse  (rnd(0, 350),rnd(0, 350) ) - (rnd(0, 350) ,rnd(0, 350) ), rnd(0, &hFFFFFF), rnd(0, 6)
        graphic inkey$ to skey
        sleep 50
    loop until skey = $esc
    '=========================================
    ' CLEAN UP SUBCLASSING
    '=========================================
    SetWindowLong(ghStatic, %GWL_WNDPROC, grStaticProc)
    '=========================================
    ' FINISHED WITH GRAPHIC WINDOW
    '=========================================
    graphic window end
end function

[Michael Mattias]

If you re-did the program as a GUI program instead of a console program, you could assign keyboard accelerators to your 'keys of interest, ' the user could then hit the magic key OR click a buttton and that would be that.

MCM
PS: My imagination or...on your linked screen the 'proof' is not a proof since the evaluation with the X and Y substitutions does not equal zero? However, it IS close (0.000000003)

[Chris Holbrook]

Nice application!

[Aimo Niemi]

PS: My imagination or...on your linked screen the 'proof' is not a proof since the evaluation with the X and Y substitutions does not equal zero? However, it IS close (0.000000003)

Yes, you are right. That is one of the reasons I am now trying to transform the code. But, have you tried to calculate the example with a windows calculator? If you have, you may have noticed that the whole example is a joke - or a mine, if you are using WIN95 calculator or some
of its earlier versions.

[Manuel Valdes]

Aimo:

Just in case. When using a loop to run an iterative or recursive routine, a way to avoid an infinite loop is to add a second stop condition (normally the right result being obtained), for instance a loop counter. So if the loop counter reach a pre-determined value then the loop ends, and you can mark the result as inaccurate. Depending on the precision of the variable you use, sometimes those routines start oscillating around the right result instead of converging, so another way is to detect that oscillation.

Regards,