ocaml: phase 5.1 bsearch.ml baseline (binary search, position sum = 7)

Iterative binary search on a sorted int array:

  let bsearch arr target =
    let n = Array.length arr in
    let lo = ref 0 and hi = ref (n - 1) in
    let found = ref (-1) in
    while !lo <= !hi && !found = -1 do
      let mid = (!lo + !hi) / 2 in
      if arr.(mid) = target then found := mid
      else if arr.(mid) < target then lo := mid + 1
      else hi := mid - 1
    done;
    !found

For [1;3;5;7;9;11;13;15;17;19;21]:
  bsearch a 13   = 6
  bsearch a 5    = 2
  bsearch a 100  = -1
  sum            = 7

Exercises Array.of_list + arr.(i) + multi-let 'let lo = ... and
hi = ...' + while + multi-arm if/else if/else.

49 baseline programs total.

lib/ocaml/baseline/bsearch.ml

@@ -0,0 +1,16 @@
+let bsearch arr target =
+  let n = Array.length arr in
+  let lo = ref 0 and hi = ref (n - 1) in
+  let found = ref (-1) in
+  while !lo <= !hi && !found = -1 do
+    let mid = (!lo + !hi) / 2 in
+    if arr.(mid) = target then found := mid
+    else if arr.(mid) < target then lo := mid + 1
+    else hi := mid - 1
+  done;
+  !found
+
+;;
+
+let a = Array.of_list [1;3;5;7;9;11;13;15;17;19;21] in
+bsearch a 13 + bsearch a 5 + bsearch a 100

lib/ocaml/baseline/expected.json

@@ -7,6 +7,7 @@
   "bfs.ml": 6,
   "btree.ml": 39,
   "brainfuck.ml": 75,
+  "bsearch.ml": 7,
   "caesar.ml": 215,
   "calc.ml": 13,
   "closures.ml": 315,