Re: CHAIN Versus SETLL and READ When Data Needed

On 2/28/07, rob@xxxxxxxxx <rob@xxxxxxxxx> wrote:

Yes, actually, it is too much to expect.  I tried to follow that rule but
it got too ugly with nested if's and stuff to put logic around each part
to see if it's time to exit
Dou KissOff;
 if this;
   //
 else;
   //
 EndIf;
 If not KissOff;
   if ...;
     //
   EndIf;
 EndIf;
 If not KissOff;
   If ...;
     //
   EndIf;
 EndIf;
 If not KissOff;
   If ...;
     //
   EndIf;
 EndIf;
EndDo;

I have to deal with similar circustances all the time - as an example, I have
a program with ten (10) consecutive procedures to execute. If any of them
fail, I want to stop processing.

I create an array (@procProxy@) containing pointers to the procedures,
each of which returns KissOff.

I then create a proxy procedure (procProxy) based upon the procedure pointer
procProxy@.

Then my code looks like this:

$I = 0;
DoU ( KissOff Or $I = %Elem(@procProxy@) );
 $I = $I + 1;
 procProxy@ = @procProxy@($I));
 KissOff = procProxy();
EndDo;


The Do loop has a true invariant, and GOTOs aren't necessary.


Chris "IMHFO" Pando
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