anchor.diff:  
   % List of expressions delimited by break
   expr_list -> eol : [].
  -expr_list -> block_expr : ['$1'].
  -expr_list -> block_expr break : ['$1'].
  +expr_list -> expr : ['$1'].
  +expr_list -> expr break : ['$1'].
   expr_list -> eol expr_list : '$2'.
  -expr_list -> block_expr break expr_list : ['$1'|'$3'].
  +expr_list -> expr break expr_list : ['$1'|'$3'].
  +
  +expr -> expr match_op expr : build_op('$2', '$1', '$3').
  +expr -> expr add_op expr : build_op('$2', '$1', '$3').
  +expr -> expr mult_op expr : build_op('$2', '$1', '$3').
  +expr -> unary_op expr : build_unary_op('$1', '$2').
  +expr -> special_op expr : build_special_op('$1', '$2').
  +expr -> block_expr : '$1'.
   
   block_expr -> dot_paren_identifier call_args_parens do_block : build_identifier('$1', '$2' ++ '$3').
   block_expr -> dot_punctuated_identifier call_args_no_parens do_block : build_identifier('$1', '$2' ++ '$3').
   block_expr -> dot_punctuated_identifier do_block : build_identifier('$1', '$2').
   block_expr -> dot_identifier call_args_no_parens do_block : build_identifier('$1', '$2' ++ '$3').
   block_expr -> dot_do_identifier do_block : build_identifier('$1', '$2').
  -block_expr -> expr : '$1'.
  -
  -expr -> expr match_op expr : build_op('$2', '$1', '$3').
  -expr -> expr add_op expr : build_op('$2', '$1', '$3').
  -expr -> expr mult_op expr : build_op('$2', '$1', '$3').
  -expr -> unary_op expr : build_unary_op('$1', '$2').
  -expr -> special_op expr : build_special_op('$1', '$2').
  -expr -> curly_expr : '$1'.
  +block_expr -> curly_expr : '$1'.
   
   curly_expr -> dot_paren_identifier call_args_parens curly_block : build_identifier('$1', '$2' ++ '$3').
   curly_expr -> dot_punctuated_identifier curly_block : build_identifier('$1', '$2').
  
positive.code: call_args_no_parens -> base_orddict : ['$1'].
  call_args_no_parens -> expr comma_separator call_args : ['$1'|'$3'].
  
  call_args -> block_expr : ['$1'].
  call_args -> base_orddict : ['$1'].
  call_args -> block_expr comma_separator call_args : ['$1'|'$3'].
  
  call_args_parens -> open_paren ')' : [].
  call_args_parens -> open_paren call_args close_paren : '$2'.
  
negative.code:   Line = ?line(Delimiter),
    [{'[]', Line, [{'{}', Line, ['do',Contents]}] }].
  
  build_identifier({ '.', DotLine, Expr, { _, Line, Identifier } }, Args) ->
    { { '.', DotLine, Expr, Identifier }, Line, Args };
  
  build_identifier({ _, Line, Identifier }, Args) ->
    { Identifier, Line, Args }.
  
  build_list(Line, Args) ->
  