anchor.diff:  //AC: keep the lexer and the parser together for now because that's the default Antlr layout
   
   options {
  -	output = template;
  -	rewrite = true;
  +    output = template;
  +    rewrite = true;
   }
   
   @parser::header {
  
positive.code:   ;
  
  matrix :
       LSQUARE FILLER? optional_row_list RSQUARE
    ;
  
  cell_array :
       LCURLY FILLER? optional_row_list RCURLY
    ;
  
  optional_row_list :
  
negative.code: 
  primary_expr :
       literal
    |  lparen FILLER? expr FILLER? rparen
    |  matrix
    |  cell_array
    |  access
  