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on [2019/06/08 22:14] – neilson [2019/06/09 08:26] (current) – [Performance tip] neils
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   on <byte or int index> goto label [ ,label ...]   on <byte or int index> goto label [ ,label ...]
 +
 +or:
 +
   on <byte or int index> gosub label [ ,label ...]   on <byte or int index> gosub label [ ,label ...]
      
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 **Note #2:** The runtime will not check if //index// is within the number of labels. If //index// is larger than the number of labels minus one, the program will (most probably) break. **Note #2:** The runtime will not check if //index// is within the number of labels. If //index// is larger than the number of labels minus one, the program will (most probably) break.
 +
 +Example:
 +
 +  rem -- i! holds a value between 0 and 2 
 +  on i! goto case0, case1, case2
 +  end
 +  case0:
 +    print "i! equals 0"
 +    end
 +  case1:
 +    print "i! equals 1"
 +    end
 +  case2:
 +    print "i! equals 2"
 +    end
 +    
 +====== Performance tip ======
 +
 +An ''ON ... GOTO'' or ''ON ... GOSUB'' construct is faster than its ''IF ... THEN GOTO/GOSUB'' equivalent. It's especially useful when branching on a TRUE/FALSE condition, for example:
 +
 +  rem -- branching using IF ... THEN
 +  rem -- assume x! is a zero or one (TRUE/FALSE) value
 +  
 +  if x! = 0 then goto false_case else goto true_case
 +  
 +  rem -- same as above but FASTER
 +  
 +  on x! goto false_case, true_case