anchor.diff:        2
     // TODO: this fails because the 'else' alias hardcodes two pipe slots, so 'with' eats the implicit pipe. 
              same thing happens for 'then', and probably other aliases. might be a symptom of the recent 
  -           pipe troubles. put some more tests in to check for it and set it right.
  +           pipe troubles. put some more tests in to check for it and set it right. (BUG)
       {0 | else "{9}" | add 1}
         1
       {0 | else "{9}" with :foo | add 1}
  
positive.code: 
  Tests for self-reference. PBV cures these ills.
    {* (:a 1 :b 2) | $>x | $>x.c}
      {"a":1,"b":2}
      
    {$x | $>x.d}
      {"a":1,"b":2,"c":{"a":1,"b":2}}
      
    {$x}
      {"a":1,"b":2,"c":{"a":1,"b":2},"d":{"a":1,"b":2,"c":{"a":1,"b":2}}}
  
negative.code: 
    GROUP
    
      // THINK: these values are all correct, but they're keyed instead of simple arrays. and, hence, sorted poorly. (BUG)
    
      {(1 2 3 4 5 6) | list group by "{__ | mod 2}"}
        [[1,3,5],[2,4,6]]
  