# Are there idioms in Julia for fast Algebraic Data Types (ADT)?

**URL:** <https://discourse.julialang.org/t/are-there-idioms-in-julia-for-fast-algebraic-data-types-adt/37244>\
**Category:** General Usage\
**Created:** [April 8, 2020, 9:14pm UTC](https://discourse.julialang.org/t/are-there-idioms-in-julia-for-fast-algebraic-data-types-adt/37244 "2020-04-08T21:14:23Z")\
**Posts on this page:** 1\
**Showing post:** 18

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**Author:** ![jonathan-laurent](https://avatars.discourse-cdn.com/v4/letter/j/ecae2f/32.png) [@jonathan-laurent](https://discourse.julialang.org/u/jonathan-laurent)\
**Post date:** [April 9, 2020, 3:42pm UTC](https://discourse.julialang.org/t/are-there-idioms-in-julia-for-fast-algebraic-data-types-adt/37244/18 "2020-04-09T15:42:53Z")

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> [@jonathan-laurent](#):
>
> So a more interesting comparison would be to compare the time it takes to evaluate the naive version in Julia with an equivalent program written in a language with native ADTs such as OCaml, Haskell or Rust. I am going to try this now.

So I did the experiment in OCaml, which is about twice as fast as the Julia version (1.61μs vs 3.23μs). This is actually not too bad for Julia and this makes me feel better about using ADTs in Julia.

### Benchmark Code

```ocaml
type expr =
  | Const of int
  | Var of string
  | Add of expr * expr

let rec evaluate expr env =
  match expr with
  | Const v -> v
  | Var x -> List.Assoc.find_exn env ~equal:String.equal x
  | Add (lhs, rhs) -> evaluate lhs env + evaluate rhs env

let rec sum_of_ints = function
  | 1 -> Const 1
  | n -> Add (Const n, sum_of_ints (n - 1))

let profile n =
  let acc = ref 0 in
  let t = Caml.Sys.time () in
  for i = 1 to n do
    acc := !acc + evaluate (sum_of_ints 100) []
  done;
  let dt = (Caml.Sys.time () -. t) /. (Float.of_int n) in
  Stdio.printf "Average time: %.3f μs" (dt *. 1e6);
  acc

let _ = profile 1000000

```

```julia-auto
Average time: 1.653 μs

```

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