anchor.diff:  
   satisfiesCaseCondition
       : 'satisfies' type
  +    -> ^(SATISFIES_EXPR type)
       ;
   
   forFail
  
positive.code: 
  satisfiesCondition
      : 'satisfies' type type
      ;
  
  controlStructure
  
negative.code:     EXISTS_EXPR;
      NONEMPTY_EXPR;
      IS_EXPR;
      SATISFIES_EXPR;
      SPECIAL_ARG;
      //PRIMARY;
  }
  