Loop Never ?

Comments

• Bean Posts: 8,129

  2007-06-19 11:23 edited 2007-06-19 11:23

  It is used to make an IF...OR constuction.
  
  Let's say you wanted to do something if (A = 1) OR (B = 2)
  
  You would use
  
  DO
  · IF A <> 1 THEN
  ··· IF B <> 2 THEN EXIT
  · ENDIF
  · ' Do whatever here
  LOOP NEVER
  
  Notice that must use the opposite condition in the IF statements (<> instead of .
  
  Bean.
  
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• sam_sam_sam Posts: 2,286

  2007-06-19 16:25 edited 2007-06-19 16:25

  Bean.
  
  
  DO
  · IF A <> 1 THEN
  ·IF B <> 2 THEN EXIT
  
  Is to mean that if A and B are not( "="· to 1 OR 2 ) then it will Not Loop
  and only goto ' Do whatever here but is that what the EXIT Dose
  
  Or is to mean that it only loop ONE TIME
  
  ·' Do whatever here
  ·
  
  LOOP NEVER
  
  I am not understanding what This Means LOOP NEVER
  
  What dose the NEVER tell it to do· or look for
  
  I understand what·LOOP means and what it dose
  I understand what· <> means NOT = to what you are looking at
  
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  Post Edited (sam_sam_sam) : 6/19/2007 4:30:13 PM GMT
• Bean Posts: 8,129

  2007-06-19 16:36 edited 2007-06-19 16:36

  [b]Let's say you wanted to do something if (A = 1) OR (B = 2)[/b]
  

  
  SX/B does not allow multiple conditions for an IF...THEN statement.
  
  But the code I posted does the same thing.
  
  "LOOP NEVER" means to never loop, or the same thing as "LOOP UNTIL A·= A"
  
  Bean.
  
  
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  “The United States is a nation of laws -· poorly written and randomly enforced.” - Frank Zappa
  
  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  www.hittconsulting.com
  ·
• JonnyMac Posts: 8,942

  2007-06-19 16:43 edited 2007-06-19 16:43

  I think what Bean is trying to say that LOOP NEVER is a convenient way to create a custom label for when your complex expression is false. Without it you could do something like this:
  
  

  Evaluation:
    IF a <> 1 THEN
      IF b <> 2 THEN
        GOTO Evaluation_Failed
      ENDIF
    ENDIF
  
  Evaluation_Succeeded:
    ' handle it
    GOTO Next_Process
  
  Evaluation_Failed:
    ' handle it
  
  Next_Process:
    ' handle it
  

  
  
  
  One of the things that the SX/B reveals is that many of our *fancy* programming structures, things like IF-THEN-ELSE, are executed with simple test-and-jump code with the compiler automating the labels that I created manually in the example above.
• sam_sam_sam Posts: 2,286

  2007-06-19 20:02 edited 2007-06-19 20:02

  JonnyMac
  
  Evaluation:
  ··IF·a·<>·1·THEN
  ····IF·b·<>·2·THEN
  ······GOTO·Evaluation_Failed
  ····ENDIF
  ··ENDIF
  
  Evaluation_Succeeded:
  ··'·handle·it
  ··GOTO·Next_Process
  
  Evaluation_Failed:
  ··'·handle·it
  
  Next_Process:
  ··'·handle·it
  
  Thank You·For explaning it this way
  Now·I understand what you are talking about
  
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  ··Thanks for any··that you may have and all of your time finding them
  
  ·
  ·
  ·
  ·
  Sam