anchor.diff:  Right     40 when_op.
   Left      50 in_op.
   Left      60 pipe_op.
  +Right     70 and_pipe_op.
   Right     80 match_op.
   Right     90 arrow_op.
   Left     100 oror_op.
  
positive.code:   matched_expr matched_op_expr unmatched_expr unmatched_op_expr
    comma_separator kv_eol
    add_op mult_op unary_op addadd_op multmult_op
    match_op arrow_op module_ref_op default_op when_op pipe_op and_concat_op in_op
    andand_op oror_op andalso_op orelse_op and_op or_op comp_expr_op
    open_paren close_paren
    open_bracket close_bracket
  
negative.code: Left     160 comp_expr_op.
  Left     170 add_op.
  Left     180 mult_op.
  Right    200 addadd_op.
  Right    210 multmult_op.
  Left     260 dot_call_op.
  