wrap example (#100)

Summary:
example use of type level module aliases technique to implement `-pack`.

Pull Request resolved: #100

Test Plan: `buck2 build root//ocaml/wrap:test-mylib`

Reviewed By: ndmitchell

Differential Revision: D43811509

Pulled By: shayne-fletcher

fbshipit-source-id: 695f47894bb8b7bdc234295731a9dbbbbf91ab6f

examples/prelude/ocaml/wrap/BUCK

@@ -0,0 +1,48 @@
+# @lint-ignore-every BUCKFORMAT
+
+# buildifier: disable=no-effect
+ocaml_library(
+    name = "_mylib",
+    compiler_flags = [
+        "-no-alias-deps",
+        "-w", "-49",
+    ],
+    srcs = [
+        "mylib.mli",
+        "mylib.ml",
+    ],
+    visibility = [ "PUBLIC" ],
+) if not host_info().os.is_windows else None
+
+export_file(
+    name= "mylib.mli",
+    src = "mylib.mli"
+)
+
+# buildifier: disable=no-effect
+ocaml_library(
+    name = "mylib",
+    ocamldep_flags = [
+        "-open", "Mylib",
+        "-map", "$(location :mylib.mli)"
+    ],
+    compiler_flags = [
+        "-no-alias-deps",
+        "-w", "-49",
+        "-open", "Mylib"
+    ],
+    srcs = [
+        "mylib__A.ml",
+        "mylib__B.ml",
+    ],
+    deps = [ ":_mylib" ],
+    visibility = [ "PUBLIC" ],
+) if not host_info().os.is_windows else None
+
+# buildifier: disable=no-effect
+ocaml_binary(
+    name = "test-mylib",
+    srcs = [ "test_Mylib.ml" ] ,
+    deps = [ ":mylib" ],
+    visibility = [ "PUBLIC" ],
+) if not host_info().os.is_windows else None

examples/prelude/ocaml/wrap/mylib.ml

@@ -0,0 +1,11 @@
+(*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under both the MIT license found in the
+ * LICENSE-MIT file in the root directory of this source tree and the Apache
+ * License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+ * of this source tree.
+ *)
+
+module A = Mylib__A
+module B = Mylib__B

examples/prelude/ocaml/wrap/mylib.mli

@@ -0,0 +1,11 @@
+(*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under both the MIT license found in the
+ * LICENSE-MIT file in the root directory of this source tree and the Apache
+ * License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+ * of this source tree.
+ *)
+
+module A = Mylib__A
+module B = Mylib__B

examples/prelude/ocaml/wrap/mylib__A.ml

@@ -0,0 +1,10 @@
+(*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under both the MIT license found in the
+ * LICENSE-MIT file in the root directory of this source tree and the Apache
+ * License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+ * of this source tree.
+ *)
+
+let print_hello () = B.print_hello ()

examples/prelude/ocaml/wrap/mylib__B.ml

@@ -0,0 +1,10 @@
+(*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under both the MIT license found in the
+ * LICENSE-MIT file in the root directory of this source tree and the Apache
+ * License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+ * of this source tree.
+ *)
+
+let print_hello () = Printf.printf "Hello!\n"

examples/prelude/ocaml/wrap/test_Mylib.ml

@@ -0,0 +1,10 @@
+(*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under both the MIT license found in the
+ * LICENSE-MIT file in the root directory of this source tree and the Apache
+ * License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+ * of this source tree.
+ *)
+
+let _: unit = Mylib.A.print_hello ()