SpiderBasic

Posted: **Wed May 20, 2015 6:37 pm**

Hi,

in PureBasic, this is a valid program:

Error = 1

If Error <> 0
  Debug "Error"
  End
EndIf

When I write that code in the SpiderBasic IDE 1.02, it looks fine as well.
Especially, "End" is highlighted as I expected, since I assumed that it is a keyword.
But when trying to run that program, SpiderBasic complains and says:

Line 5: Syntax error.

When I put the cursor on "End" and press [F1], then the Spiderbasic help is opened, showing the page "Other Commands".
However, "End" is nowhere mentioned on that page.

All this is a bit confusing, I think there are probably some leftovers from the PB IDE and help.

If "End" actually is not a SpiderBasic keyword, how can I terminate a program, e.g. in case of an error?

Posted: **Thu May 21, 2015 6:18 am**

No, 'End' is is not a SB keyword. You can not "terminate" a program in SB, as it means you will close the browser page (and it's not allowed). Or do you have another use of 'End' in mind ?

Posted: **Thu May 21, 2015 7:06 pm**

Yes, I have another use of 'End' in mind.
I'll try to give better examples of what I mean.

This code works fine in PB and SB as well:

Code: Select all

If OpenWindow(0, 100, 200, 320, 200, "Test", #PB_Window_TitleBar)
   If CreateImage(0, 320, 200)
      If StartDrawing(ImageOutput(0))
         ; [...]
      Else
         Debug "Can't start drawing."
      EndIf
   Else
      Debug "Can't create image."
   EndIf
   ; [...]
Else
   Debug "Can't open window."
EndIf

Depending on the actual code, sometimes I prefer to write the same stuff in a different way.
The following code is logically equivalent to the first one, but runs only in PB:

Code: Select all

If OpenWindow(0, 100, 200, 320, 200, "Test", #PB_Window_TitleBar) = 0
   Debug "Can't open window."
   End
EndIf

If CreateImage(0, 320, 200) = 0
   Debug "Can't create image."
   End
EndIf

If StartDrawing(ImageOutput(0)) = 0
   Debug "Can't start drawing."
   End
EndIf

; [...]

; [...]

When I want to run that program in SB, I have to rewrite the code.
I would greatly appreciate it if that code would run in SB, too -- if possible.

I'm aware that I can write it in SB (and PB) like this:

Code: Select all

Procedure Main()
   If OpenWindow(0, 100, 200, 320, 200, "Test", #PB_Window_TitleBar) = 0
      Debug "Can't open window."
      ProcedureReturn
   EndIf
   
   If CreateImage(0, 320, 200) = 0
      Debug "Can't create image."
      ProcedureReturn
   EndIf
   
   If StartDrawing(ImageOutput(0)) = 0
      Debug "Can't start drawing."
      ProcedureReturn
   EndIf
   
   ; [...]
   
   ; [...]
EndProcedure


Main()

But that would also mean rewriting the original PB code.

Posted: **Thu May 21, 2015 8:34 pm**

But what should happen when your web app ends? Close the browser tab (as Fred said) or start an endless loop that does nothing? The only thing you could do in your case is to show something like a permanent failure message.
Apart from that "End" simply doesn't make sense in the WWW-world. I think the only problem here is that the SB IDE shouldn't detect it as a valid keyword.

Posted: **Fri May 22, 2015 4:56 am**

c4s wrote:But what should happen when your web app ends?

What happens in this code, when OpenWindow() returns 0?

Code: Select all

If OpenWindow(0, 100, 200, 320, 200, "Test", #PB_Window_TitleBar)
   If CreateImage(0, 320, 200)
      ; [...]
   EndIf
EndIf

Whatever happens, I thought the same could happen in the following code, when OpenWindow() returns 0:

Code: Select all

If OpenWindow(0, 100, 200, 320, 200, "Test", #PB_Window_TitleBar) = 0
   End   
EndIf

If CreateImage(0, 320, 200) = 0
   End
EndIf

; [...]

c4s wrote:[...] show something like a permanent failure message.

That's a good idea IMHO.

Code: Select all

If OpenWindow(0, 100, 200, 320, 200, "Test", #PB_Window_TitleBar) = 0
   End "Fatal error: Can't open main window."
EndIf

Since I cannot use 'End', how am I supposed to handle a fatal error in my code, e.g. when OpenWindow() returns 0?

Posted: **Fri May 22, 2015 6:39 am**

IMHO, you should write your own End() procedure and do appropriate action when you are in PB or SB. In SB, you will probably open a window with a message like "Fatal error occured". We could accept End in SB and close every objects automatically (window, image etc.) but you will end up with a brown empty window and I don't think it's really what you want.

If you don't want to change your PB code, you can also use a Macro

Posted: **Sat May 23, 2015 1:06 pm**

Fred and c4s, thanks for your answers!
I hope I'll soon learn the principle differences between a PB executable and a SB web app.

SpiderBasic

Is "End" a SpiderBasic keyword?

Is "End" a SpiderBasic keyword?

Re: Is "End" a SpiderBasic keyword?

Re: Is "End" a SpiderBasic keyword?

Re: Is "End" a SpiderBasic keyword?

Re: Is "End" a SpiderBasic keyword?

Re: Is "End" a SpiderBasic keyword?

Re: Is "End" a SpiderBasic keyword?