Associative-stuff, ocaml api

Learning
1

I’m trying to do some associative stuff.
But there are different types possible.

  1. association-lists
  2. maps
  3. hash-tables
  4. associative-arrays
    What are the ocaml API’s to do this ?
    I know there is Jane-Streeth, but it looks a waste of time. Because you need a community to go somewhere.
2

Hi, modules for all of the above are in the OCaml standard library. Have you tried there?

3
  • Association lists
  • Maps (to create a map module for a specific type for which there exists a total ordering comparison function, you have to use the functor Map.Make, whose output signature provides the typical functions for working with maps)
  • Hash tables (side-effectful interface)
  • Associative arrays—maps are associative arrays
4

What does that even mean?

Jane Street base has a convenient List.Assoc module to deal with association list. That’s often the most convienient way to interop with a lot of associative APIs since that’s what libraries like e.g. Yojson return.

Maps vs Hashtables is a question of whether you want the data structure to be mutable or not. There’s cases for both, but most of the time I would go with a map, especially if returning some data to a consumer. For the common case that the key is a string, Base has String.Map and String.Table so you don’t need to write your own functor, which is somewhat conventient.

5

If you are interested to associate string with something, you should take look on art which has better performances than Hashtbl :slight_smile: