Toy example of reason codegen

belt_Array.js

function forEachU(a, f) {
  for(var i = 0 ,i_finish = a.length - 1 | 0; i <= i_finish; ++i){
    f(a[i]);
  }
  return /* () */0;
}

function forEach(a, f) {
  return forEachU(a, Curry.__1(f));
}

/* export */

curry.js

function __1(o) {
  var arity = o.length;
  if (arity === 1) {
    return o;
  } else {
    return (function (a0) {
        return _1(o, a0);
      });
  }
}

/* export */

stdlib_Block.js

function __(tag, block) {
  block.tag = tag;
  return block;
}
/* export */

Tree.bs.js

// Generated by BUCKLESCRIPT VERSION 2.2.3, PLEASE EDIT WITH CARE

import * as Block from "stdlib/block";
import * Belt_Array from "stdlib/belt_Array";

function depthFirstTraversal(param) {
  if (typeof param === "number") {
    return /* array */[];
  } else if (param.tag) {
    var match = param[0];
    return Belt_Array.concatMany(/* array */[
                depthFirstTraversal(match[1]),
                /* array */[match[0]],
                depthFirstTraversal(match[2])
              ]);
  } else {
    return /* array */[param[0]];
  }
}

var tree = /* Node */Block.__(1, [/* tuple */[
      6,
      /* Node */Block.__(1, [/* tuple */[
            5,
            /* Leaf */Block.__(0, [4]),
            /* Empty */0
          ]]),
      /* Node */Block.__(1, [/* tuple */[
            8,
            /* Empty */0,
            /* Leaf */Block.__(0, [9])
          ]])
    ]]);

Belt_Array.forEach(depthFirstTraversal(tree), (function (prim) {
        console.log(prim);
        return /* () */0;
      }));

export {
  depthFirstTraversal ,
  tree ,
}
/*  Not a pure module */

Tree.re

open Belt;

type Tree('a) = 
  | Empty
  | Leaf('a)
  | Node('a, Tree('a), Tree('a));

let rec depthFirstTraversal: Tree => array('a) = (tree) => {
  switch (tree) {
    | Empty => [||]
    | Leaf(x) => [|x|]
    | Node(x, left, right) => [|
      depthFirstTraversal(left),
      [|x|],
      depthFirstTraversal(right)
      |] |. Array.concatMany
  }
};

let tree = Node(6, Node(5, Leaf(4), Empty), Node(8, Empty, Node(9)));


tree |. depthFirstTraversal |. Js.log;