parsing_c/token_annot.ml

   1 (* Provides a dictionary of possible annotations on tokens, indexed by keys.
   2  *
   3  * The purpose of these annotations is to direct the pretty printing of
   4  * tokens. The annotations can be set by AST transformations.
   5  *
   6  * Assumptions: only a few tokens have annotations, and those have only
   7  * a few of them.
   8  *)
   9
  10 type annot_key =
  11     Exclude_start
  12   | Exclude_end
  13
  14 type annot_val =
  15   Unit
  16
  17 (* A linked list should offer a good tradeoff between space usage
  18  * and lookup overhead given our assumptions.
  19  *)
  20 type annots = (annot_key * annot_val) list
  21
  22 let empty = []
  23
  24 let get_annot anns key =
  25   if List.mem_assoc key anns
  26   then Some (List.assoc key anns)
  27   else None
  28
  29 let put_annot key value anns =
  30   (key, value) :: anns