From: dxforth@gmail.com   
      
   On 13/10/2024 12:54 am, Ruvim wrote:   
   > On 2024-10-12 05:45, dxf wrote:   
   >> The basics:   
   >>   
   >> : .BAD ( -- )  cr ." Invalid item"  .abort ;   
   >>   
   >> : ZE? ( x -- )  if .bad then ;     \ abort if non-zero   
   >> : NZ? ( x -- )  0= ze? ;           \ abort if zero   
   >   
   > Typically, if word name ends with a question mark, the first (top) output   
   parameter of the word is a *flag*. And it's true for all standard words.   
   (though, opposite is not true)   
      
   It's rather similar.   
      
   ZE? NZ?  destructively tests TOS   
   ?ZE ?NZ  non-destructively tests TOS   
      
   Only difference is test and action are rolled into the one function.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)