anchor.diff:  table(?EXPR, string) -> [string,{reduce,3}];
   table(?EXPR, binary) -> [binary,{reduce,21}];
   table(?EXPR, '#\'') -> ['#\'',{reduce,4}];
  +table(?EXPR, '#.') -> ['#.',?EXPR,{reduce,22}];
   table(?EXPR, '\'') -> ['\'',?EXPR,{reduce,5}];
   table(?EXPR, '`') -> ['`',?EXPR,{reduce,6}];
   table(?EXPR, ',') -> [',',?EXPR,{reduce,7}];
  
positive.code: %%  3 sexpr -> string : val('$1').
  %% 21 sexpr -> binary : val('$1').
  %%  4 sexpr -> '#\'' : make_fun(val('$1')).
  %%  5 sexpr -> '\'' sexpr : [quote,'$2'].
  %%  6 sexpr -> '`' sexpr : [backquote,'$2'].
  %%  7 sexpr -> ',' sexpr : [unquote,'$2'].
  
negative.code: table(?FORM, string) -> [?EXPR];
  table(?FORM, binary) -> [?EXPR];
  table(?FORM, '#\'') -> [?EXPR];
  table(?FORM, '#.') -> [?EXPR];
  table(?FORM, '\'') -> [?EXPR];
  table(?FORM, '`') -> [?EXPR];
  table(?FORM, ',') -> [?EXPR];
  