From: krishna.myneni@ccreweb.org   
      
   On 6/27/24 14:09, Krishna Myneni wrote:   
   > On 6/26/24 23:14, Gerry Jackson wrote:   
   >> On 26/06/2024 14:36, Ruvim wrote:   
   >>> One possible use case:   
   >>>   
   >>>    : turnkey ( -- ) 0 set-order   
   >>>      also Target definitions   
   >>>      also Minimal also   
   >>>    ;   
   >>   
   >> ALSO duplicates the wordlist at the head of the search order. If the   
   >> search order is empty there is nothing to duplicate. Therefore ALSO   
   >> applied to an empty search order ought to be an ambiguous condition.   
   >>   
   >> Presumably the above definition works because a target wordlist   
   >> replaces whatever garbage ALSO leaves in the search order. So the   
   >> definition might as well have 0 1 SET-ORDER instead of 0 SET-ORDER ALSO.   
   >> Or better still TARGET-WORDLIST 1 SET-ORDER. Either removes the above   
   >> justification for 0 SET-ORDER.   
   >>   
   >   
   > Good analysis showing that   
   >   
   > 1) The definition of TURNKEY is flawed.   
   >   
   > 2) 0 SET-ORDER is not necessary.   
   >   
   >   
   >> But having said that it is better for 0 SET-ORDER to do what is   
   >> natural instead of yet another ambiguous condition.   
   >>   
   >>  > Another possible use case:   
   >>  >   
   >>  >    : s-to-n ( addr u -- n )   
   >>  >      depth >r   
   >>  >      get-order n>r 0 set-order   
   >>  >        ['] evaluate ['] execute-interpreting catch   
   >>  >      nr> set-order   
   >>  >      depth 1- r> <> if -12 throw then   
   >>  >    ;   
   >>   
   >> This is a better use case e.g. if BASE is greater than decimal 10   
   >> converting an alphanumeric string to a number could clash with a word   
   >> in the dictionary. Having an empty search order eliminates that   
   >> possibility.   
   >>   
   >   
   > This use case is convoluted and there may be a better of dealing with   
   > the anticipated problem. If not, we should consider what's missing in   
   > Forth allowing us to solve the problem more directly.   
   >   
   >   
   > No one has pointed to a need for 0 SET-ORDER in interpretation state,   
   > and there is no to undo its use in interpretation state in a standard.   
   > Furthermore an empty search order contradicts the concept of a minimum   
   > search order.   
   >   
   > The solutions are:   
   >   
   > 1) leave everything as is, and live with the contradiction and the   
   > hazard of performing 0 SET-ORDER in interpretation state.   
   >   
   > 2) make SET-ORDER state-smart, and live with the contradiction. This   
   > will potentially break code.   
   >   
   > 3) disallow zero as an argument to SET-ORDER e.g. throw an error for zero.   
   >   
   > Am I missing any other options?   
   >   
   > Personally, I favor 3) -- throwing an error when zero is an argument to   
   > SET-ORDER.   
   >   
      
   Edits:   
      
   No one has pointed to a need for 0 SET-ORDER in interpretation state,   
   and there is no standard way to undo its use in interpretation state.   
      
   3) disallow zero as an argument to SET-ORDER e.g. throw an error for   
   zero. This will break existing code where zero is an argument to SET-ORDER.   
      
   Any idea of frequency of usage for 0 SET-ORDER . I don't believe I have   
   ever used it in a definition.   
      
   --   
   KM   
      
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