diff --git a/.eslintignore b/.eslintignore
index fa90e51b..a14bf52c 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,4 +1,5 @@
 /node_modules
 src/modules/create-knit-app/template
+lib
 dist
 build
diff --git a/.gitignore b/.gitignore
index f2632dfa..d34bb912 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,10 +29,14 @@ coverage
 .idea
 *.iml
 .vscode
+.merlin
 
 # build folders
 build
 dist
+**/lib/bs
+**/lib/ocaml
+/lib
 
 # OS
 .DS_Store
diff --git a/bsconfig.json b/bsconfig.json
new file mode 100644
index 00000000..dd3d3170
--- /dev/null
+++ b/bsconfig.json
@@ -0,0 +1,16 @@
+{
+  "name": "this_just_for_the_root_merlin_file_for_text_editor",
+  "sources": [
+    {
+      "dir": "src",
+      "subdirs": []
+    }
+  ],
+  "bs-dev-dependencies": [
+    "immutable-re",
+    "@knit/is-scoped",
+    "@knit/path-join",
+    "@knit/read-pkg"
+  ],
+  "generate-merlin": true
+}
\ No newline at end of file
diff --git a/package-lock.json b/package-lock.json
index bda75c0e..820d0210 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,7 +1,7 @@
 {
   "version": "0.4.1",
   "lockfileVersion": 1,
-  "packageIntegrity": "sha512-VsvokrBAs2H4u0XIEyv7ZKIxG4GkEAdZepZt86Oc8CXuIdoujJ7JrffLK7+V49gewnzpaNlOPzEZHCEVLGDbCQ==",
+  "packageIntegrity": "sha512-/wYd1J1NAAdP8nrpjAL3QI0Ev+dsUgpgAPDCQAHeo8zl8Ytg8ukvQRChQuN2uHGAIruju4LPWeReGq/y9be9yw==",
   "dependencies": {
     "@knit/babel-preset-socks-react": {
       "version": "file:src/modules/@knit/babel-preset-socks-react",
@@ -921,6 +921,11 @@
       "resolved": "https://registry.npmjs.org/browserslist/-/browserslist-2.1.3.tgz",
       "integrity": "sha1-MC3I5eRPPVk3hQhoqrE+EcrD28c="
     },
+    "bs-platform": {
+      "version": "1.7.3",
+      "resolved": "https://registry.npmjs.org/bs-platform/-/bs-platform-1.7.3.tgz",
+      "integrity": "sha1-g94BNK/9xyNUVHfOc3YGhH2nAQQ="
+    },
     "bser": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/bser/-/bser-2.0.0.tgz",
@@ -2995,6 +3000,11 @@
       "integrity": "sha1-QyNS5XrM2HqzEQ6C0/6g5HgSFW0=",
       "dev": true
     },
+    "immutable-re": {
+      "version": "0.0.15",
+      "resolved": "https://registry.npmjs.org/immutable-re/-/immutable-re-0.0.15.tgz",
+      "integrity": "sha1-Vqma12R5pf/T/M7BPsK4U9HrzjE="
+    },
     "imurmurhash": {
       "version": "0.1.4",
       "resolved": "https://registry.npmjs.org/imurmurhash/-/imurmurhash-0.1.4.tgz",
diff --git a/package.json b/package.json
index e78e22c3..39c94653 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,7 @@
     "file-loader": "^0.10.1",
     "fs-extra": "^3.0.1",
     "html-webpack-plugin": "^2.28.0",
+    "immutable-re": "0.0.15",
     "json-loader": "^0.5.4",
     "listr": "^0.12.0",
     "listr-silent-renderer": "^1.1.1",
@@ -61,10 +62,13 @@
   },
   "scripts": {
     "precommit": "lint-staged",
-    "copy": "rm -rf dist && rm -rf build && yarn knit -- copy --ignore-path=@knit/**/{__mocks__,__tests__,*.js}",
+    "copy": "rm -rf dist && rm -rf build && yarn knit -- copy --ignore-path=@knit/**/{__mocks__,__tests__,bs,*.js,*.re,}",
     "build-lib": "NODE_ENV=production babel src/modules/ -d dist/ --ignore __mocks__,__tests__,jest,create",
     "build-cjs": "NODE_ENV=production yarn knit -- exec --concurrently --scope modified --include=@knit --exclude=jest -- babel . -d ROOT_DIR/dist/KNIT_MODULE_NAME --ignore __mocks__,__tests__,jest,create",
-    "build-packages": "yarn copy && yarn build-cjs && yarn knit -- stitch --scope modified",
+    "build-bsb": "NODE_ENV=production yarn knit -- exec --concurrently --include=is-scoped path-join read-pkg -- bsb -make-world",
+    "build-ocaml": "yarn knit -- exec --concurrently --include=is-scoped path-join read-pkg -- knit copy --workingDir lib/bs --outputDir lib/ocaml",
+    "build-bsb-w": "NODE_ENV=production yarn knit -- exec --concurrently --include=is-scoped path-join read-pkg -- bsb -w",
+    "build-packages": "yarn build-bsb && yarn copy && yarn build-cjs && yarn knit -- stitch --scope modified",
     "version": "yarn knit -- exec --scope modified -- npm version --no-git-tag-version $npm_package_version && git add .",
     "publish-packages": "yarn knit -- exec --scope unpublished --working-dir build -- npm publish",
     "knit": "babel-node src/modules/@knit/knit/bin/cli.js",
@@ -109,6 +113,7 @@
     "babel-plugin-array-includes": "2.0.3",
     "babel-plugin-transform-flow-strip-types": "^6.22.0",
     "babel-plugin-transform-runtime": "^6.23.0",
+    "bs-platform": "1.7.3",
     "eslint": "^3.16.1",
     "eslint-config-google": "0.7.1",
     "eslint-config-prettier": "2.1.1",
diff --git a/src/modules/@knit/find-dependencies/index.js b/src/modules/@knit/find-dependencies/index.js
index a04cebec..ca884d04 100644
--- a/src/modules/@knit/find-dependencies/index.js
+++ b/src/modules/@knit/find-dependencies/index.js
@@ -3,7 +3,7 @@
 import type { TPkgJson, TPkgJsonDeps } from "@knit/needle";
 
 import depcheck from "@knit/depcheck";
-import pathJoin from "@knit/path-join";
+import { pathJoin } from "@knit/path-join";
 import readPkg from "@knit/read-pkg";
 
 export type TModules = Array<string>;
diff --git a/src/modules/@knit/find-modified-packages/index.js b/src/modules/@knit/find-modified-packages/index.js
index fc4ed5e6..a8f4ad34 100644
--- a/src/modules/@knit/find-modified-packages/index.js
+++ b/src/modules/@knit/find-modified-packages/index.js
@@ -5,7 +5,7 @@ import type { TModules } from "@knit/knit-core";
 import execa from "execa";
 
 import { makeDependencyMap } from "@knit/find-dependencies";
-import isScoped from "@knit/is-scoped";
+import { isScoped } from "@knit/is-scoped";
 
 type TResolveCascadingUpdates = (
   modules: TModules,
diff --git a/src/modules/@knit/find-packages/index.js b/src/modules/@knit/find-packages/index.js
index 7abdad66..29a72d32 100644
--- a/src/modules/@knit/find-packages/index.js
+++ b/src/modules/@knit/find-packages/index.js
@@ -2,8 +2,8 @@
 
 import fs from "fs-extra";
 
-import isScoped from "@knit/is-scoped";
-import pathJoin from "@knit/path-join";
+import { isScoped } from "@knit/is-scoped";
+import { pathJoin } from "@knit/path-join";
 import getPackageFromDir from "@knit/get-package-from-dir";
 import readPkg from "@knit/read-pkg";
 
diff --git a/src/modules/@knit/is-scoped/IsScoped.re b/src/modules/@knit/is-scoped/IsScoped.re
new file mode 100644
index 00000000..01a3d638
--- /dev/null
+++ b/src/modules/@knit/is-scoped/IsScoped.re
@@ -0,0 +1,3 @@
+/*let isScoped package => package.[0] === '@';*/
+let isScoped (package: string) :Js.boolean =>
+  Js.Boolean.to_js_boolean (Js.String.get package 0 === "@");
\ No newline at end of file
diff --git a/src/modules/@knit/is-scoped/__tests__/unit.test.js b/src/modules/@knit/is-scoped/__tests__/unit.test.js
index e8aabce6..0149b982 100644
--- a/src/modules/@knit/is-scoped/__tests__/unit.test.js
+++ b/src/modules/@knit/is-scoped/__tests__/unit.test.js
@@ -1,4 +1,4 @@
-const is = require("..");
+import { isScoped as is } from "..";
 
 describe("isScoped", () => {
   it("knows if package is scoped", () => {
diff --git a/src/modules/@knit/is-scoped/bsconfig.json b/src/modules/@knit/is-scoped/bsconfig.json
new file mode 100644
index 00000000..9003ebb1
--- /dev/null
+++ b/src/modules/@knit/is-scoped/bsconfig.json
@@ -0,0 +1,9 @@
+{
+  "name": "@knit/is-scoped",
+  "sources": ".",
+  "package-specs": ["commonjs"],
+  "bsc-flags": [
+    "-bs-cross-module-opt"
+  ],
+  "generate-merlin": false
+}
diff --git a/src/modules/@knit/is-scoped/index.js b/src/modules/@knit/is-scoped/index.js
index ebfe844e..a6decebb 100644
--- a/src/modules/@knit/is-scoped/index.js
+++ b/src/modules/@knit/is-scoped/index.js
@@ -3,4 +3,4 @@
 type TIsScoped = (m: string) => boolean;
 const isScoped: TIsScoped = module => module[0] === "@";
 
-export default isScoped;
+export { isScoped };
diff --git a/src/modules/@knit/is-scoped/lib/js/isScoped.js b/src/modules/@knit/is-scoped/lib/js/isScoped.js
new file mode 100644
index 00000000..9638a0fb
--- /dev/null
+++ b/src/modules/@knit/is-scoped/lib/js/isScoped.js
@@ -0,0 +1,15 @@
+// Generated by BUCKLESCRIPT VERSION 1.7.3, PLEASE EDIT WITH CARE
+'use strict';
+
+
+function isScoped($$package) {
+  var b = +($$package[0] === "@");
+  if (b) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+exports.isScoped = isScoped;
+/* No side effect */
diff --git a/src/modules/@knit/is-scoped/package.json b/src/modules/@knit/is-scoped/package.json
index b5e215ed..e86390a6 100644
--- a/src/modules/@knit/is-scoped/package.json
+++ b/src/modules/@knit/is-scoped/package.json
@@ -1,4 +1,5 @@
 {
   "name": "@knit/is-scoped",
-  "version": "0.4.0"
+  "version": "0.4.0",
+  "main": "lib/js/isScoped"
 }
diff --git a/src/modules/@knit/knit/tasks/exec.js b/src/modules/@knit/knit/tasks/exec.js
index 6f5377ce..19cde72b 100644
--- a/src/modules/@knit/knit/tasks/exec.js
+++ b/src/modules/@knit/knit/tasks/exec.js
@@ -5,7 +5,7 @@ import type { TModules } from "@knit/knit-core";
 const Listr = require("listr");
 
 const needle = require("@knit/needle");
-const pathJoin = require("@knit/path-join");
+import { pathJoin } from "@knit/path-join";
 const execa = require("execa");
 
 type TCtx = {
diff --git a/src/modules/@knit/knit/tasks/publish.js b/src/modules/@knit/knit/tasks/publish.js
index 650f0545..cad9bd1e 100644
--- a/src/modules/@knit/knit/tasks/publish.js
+++ b/src/modules/@knit/knit/tasks/publish.js
@@ -7,7 +7,7 @@ import yarn from "@knit/yarn-utils";
 
 const Listr = require("listr");
 
-const pathJoin = require("@knit/path-join");
+import { pathJoin } from "@knit/path-join";
 const needle = require("@knit/needle");
 
 type TCtx = {
diff --git a/src/modules/@knit/knit/tasks/run.js b/src/modules/@knit/knit/tasks/run.js
index 075aafd5..c68ea79d 100644
--- a/src/modules/@knit/knit/tasks/run.js
+++ b/src/modules/@knit/knit/tasks/run.js
@@ -6,7 +6,7 @@ import readPkg from "@knit/read-pkg";
 
 const Listr = require("listr");
 
-const pathJoin = require("@knit/path-join");
+import { pathJoin } from "@knit/path-join";
 const needle = require("@knit/needle");
 const yarn = require("@knit/yarn-utils");
 
diff --git a/src/modules/@knit/knit/tasks/stitch.js b/src/modules/@knit/knit/tasks/stitch.js
index f844ee72..3de51cd9 100644
--- a/src/modules/@knit/knit/tasks/stitch.js
+++ b/src/modules/@knit/knit/tasks/stitch.js
@@ -9,7 +9,7 @@ import writePkg from "write-pkg";
 import { findDependencies } from "@knit/find-dependencies";
 
 const knit = require("@knit/knit-core");
-const pathJoin = require("@knit/path-join");
+import { pathJoin } from "@knit/path-join";
 const needle = require("@knit/needle");
 
 type TCtx = {
diff --git a/src/modules/@knit/path-join/PathJoin.re b/src/modules/@knit/path-join/PathJoin.re
new file mode 100644
index 00000000..8b1baba2
--- /dev/null
+++ b/src/modules/@knit/path-join/PathJoin.re
@@ -0,0 +1,5 @@
+external join : string => string => string = "" [@@bs.module "path"];
+
+external sep : string = "" [@@bs.module "path"];
+
+let pathJoin dir_path package => Js.String.replace "/" sep (join dir_path package);
\ No newline at end of file
diff --git a/src/modules/@knit/path-join/__tests__/unit.test.js b/src/modules/@knit/path-join/__tests__/unit.test.js
index 14940128..84bc4d8f 100644
--- a/src/modules/@knit/path-join/__tests__/unit.test.js
+++ b/src/modules/@knit/path-join/__tests__/unit.test.js
@@ -2,20 +2,15 @@
 
 const path = require("path");
 
-const pj = require("..");
+import { pathJoin as pj } from "..";
 
 describe("pathJoin", () => {
-  it("still works like path.join", () => {
-    expect(pj("foo", "bar", "module")).toBe(path.join("foo", "bar", "module"));
-  });
   it("create path when passed scoped module", () => {
-    expect(pj("foo", "bar", "@scope/package")).toBe(
-      path.join("foo", "bar", "@scope", "package")
+    expect(pj("foo", "@scope/package")).toBe(
+      path.join("foo", "@scope", "package")
     );
   });
   it("keep abs path", () => {
-    expect(pj("/foo", "bar", "package")).toBe(
-      path.join("/foo", "bar", "package")
-    );
+    expect(pj("/foo", "package")).toBe(path.join("/foo", "package"));
   });
 });
diff --git a/src/modules/@knit/path-join/bsconfig.json b/src/modules/@knit/path-join/bsconfig.json
new file mode 100644
index 00000000..4d6f7ed5
--- /dev/null
+++ b/src/modules/@knit/path-join/bsconfig.json
@@ -0,0 +1,9 @@
+{
+  "name": "@knit/path-join",
+  "sources": ".",
+  "package-specs": ["commonjs"],
+  "bsc-flags": [
+    "-bs-cross-module-opt"
+  ],
+  "generate-merlin": false
+}
diff --git a/src/modules/@knit/path-join/index.js b/src/modules/@knit/path-join/index.js
index 3a7fcd58..53bbc071 100644
--- a/src/modules/@knit/path-join/index.js
+++ b/src/modules/@knit/path-join/index.js
@@ -6,4 +6,4 @@ type TPathJoin = (p: string) => string;
 const pathJoin: TPathJoin = (...paths) =>
   path.join(...paths).replace("/", path.sep);
 
-module.exports = pathJoin;
+export { pathJoin };
diff --git a/src/modules/@knit/path-join/lib/js/pathJoin.js b/src/modules/@knit/path-join/lib/js/pathJoin.js
new file mode 100644
index 00000000..6746c7ee
--- /dev/null
+++ b/src/modules/@knit/path-join/lib/js/pathJoin.js
@@ -0,0 +1,11 @@
+// Generated by BUCKLESCRIPT VERSION 1.7.3, PLEASE EDIT WITH CARE
+'use strict';
+
+var Path = require("path");
+
+function pathJoin(dir_path, $$package) {
+  return Path.join(dir_path, $$package).replace("/", Path.sep);
+}
+
+exports.pathJoin = pathJoin;
+/* path Not a pure module */
diff --git a/src/modules/@knit/path-join/package.json b/src/modules/@knit/path-join/package.json
index e91b1daf..f026a989 100644
--- a/src/modules/@knit/path-join/package.json
+++ b/src/modules/@knit/path-join/package.json
@@ -1,4 +1,5 @@
 {
   "name": "@knit/path-join",
-  "version": "0.4.0"
+  "version": "0.4.0",
+  "main": "lib/js/pathJoin"
 }
diff --git a/src/modules/@knit/read-pkg/ReadPkg.re b/src/modules/@knit/read-pkg/ReadPkg.re
new file mode 100644
index 00000000..82738d9c
--- /dev/null
+++ b/src/modules/@knit/read-pkg/ReadPkg.re
@@ -0,0 +1,8 @@
+type syncOptions = {normalize: bool};
+
+external sync : Js.String.t => syncOptions => string = "" [@@bs.module "read-pkg"];
+
+let readPkg dir_path package => {
+  let ret = sync (PathJoin.pathJoin dir_path package) {normalize: false};
+  ()
+};
\ No newline at end of file
diff --git a/src/modules/@knit/read-pkg/bsconfig.json b/src/modules/@knit/read-pkg/bsconfig.json
new file mode 100644
index 00000000..a01bbeb0
--- /dev/null
+++ b/src/modules/@knit/read-pkg/bsconfig.json
@@ -0,0 +1,12 @@
+{
+  "name": "@knit/read-pkg",
+  "sources": ".",
+  "package-specs": ["commonjs"],
+  "bsc-flags": [
+    "-bs-cross-module-opt"
+  ],
+  "bs-dependencies": [
+    "@knit/path-join"
+  ],
+  "generate-merlin": false
+}
diff --git a/src/modules/@knit/read-pkg/index.js b/src/modules/@knit/read-pkg/index.js
index 1a804132..1f14e985 100644
--- a/src/modules/@knit/read-pkg/index.js
+++ b/src/modules/@knit/read-pkg/index.js
@@ -2,7 +2,7 @@
 
 import rp from "read-pkg";
 
-import pathJoin from "@knit/path-join";
+import { pathJoin } from "@knit/path-join";
 
 import type { TPkgJson } from "@knit/needle";
 
diff --git a/src/modules/@knit/read-pkg/lib/js/readPkg.js b/src/modules/@knit/read-pkg/lib/js/readPkg.js
new file mode 100644
index 00000000..66b71c85
--- /dev/null
+++ b/src/modules/@knit/read-pkg/lib/js/readPkg.js
@@ -0,0 +1,13 @@
+// Generated by BUCKLESCRIPT VERSION 1.7.3, PLEASE EDIT WITH CARE
+'use strict';
+
+var PathJoin = require("@knit/path-join/lib/js/pathJoin.js");
+var ReadPkg  = require("read-pkg");
+
+function readPkg(dir_path, $$package) {
+  ReadPkg.sync(PathJoin.pathJoin(dir_path, $$package), /* record */[/* normalize : false */0]);
+  return /* () */0;
+}
+
+exports.readPkg = readPkg;
+/* PathJoin Not a pure module */