From: bqt@softjar.se   
      
   On 2025-01-31 16:18, Arne Vajhøj wrote:   
   > Is it common to use:   
   >   
   > declare integer constant TRUE = -1   
   > declare integer constant FALSE = 0   
   >   
   >   
   > ?   
      
   After reading through this thread, I can offer a comment or two that   
   I've not seen anyone else bring up (and sorry for reviving a thread that   
   had stopped).   
      
   But first of all, while I haven't often seen those declarations as such,   
   they make perfect sense in BASIC.   
      
   What noone seems to have brought up is that BASIC don't really have a   
   boolean type, or logical operations on booleans.   
      
   There is no boolean AND for instance. There is only the numerical one.   
      
   If you do a statement like:   
      
   IF 1% AND 2% THEN PRINT "All true" ELSE PRINT "All false"   
      
   you'll get "All false".   
      
   Because while 1 and 2 both will be regarded as true (or rather not   
   false), AND isn't dealing with them that way. It just does a binary and   
   of the two values, and then you have an IF on the resulting value (which   
   would be 0 in this case).   
      
   So in that sense, it is good practice to use -1 for true, because then   
   at least TRUE and (whatever not false) is still (sortof) true.   
      
   It's also easy to observe that BASIC actually generally use -1 to   
   represent true.   
      
   Just try:   
      
   PRINT 1=1   
      
   for example. The output will be -1.   
      
   Here are the cut-n-paste from BASIC+2 for this:   
      
   .bp2   
      
   PDP-11 BASIC-PLUS-2 V2.7-C   
      
   BASIC2   
      
   print 1=1   
      
      
   -1   
      
   BASIC2   
      
   IF 1% AND 2% THEN PRINT "All true" ELSE PRINT "All false"   
      
      
   All false   
      
   BASIC2   
      
      
      
      Johnny   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)