Add Compile Reason With An OCaml Package Using Dune as a reason til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_713 TILs and counting..._
+_714 TILs and counting..._
 
 ---
 
@@ -512,6 +512,7 @@ _713 TILs and counting..._
 
 - [Break Out Of A While Loop](reason/break-out-of-a-while-loop.md)
 - [Compile Reason To Native With Dune](reason/compile-reason-to-native-with-dune.md)
+- [Compile Reason With An OCaml Package Using Dune](reason/compile-reason-with-an-ocaml-package-using-dune.md)
 - [Create A Stream From An Array](reason/create-a-stream-from-an-array.md)
 - [Data Structures With Self-Referential Types](reason/data-structures-with-self-referential-types.md)
 - [Defining Variants With Constructor Arguments](reason/defining-variants-with-constructor-arguments.md)

reason/compile-reason-with-an-ocaml-package-using-dune.md

@@ -0,0 +1,35 @@
+# Compile Reason With An OCaml Package Using Dune
+
+In [Compile Reason To Native With
+Dune](reason/compile-reason-to-native-with-dune.md), I showed how to compile
+a basic ReasonML file as a native executable using Dune.
+
+Any non-trivial program will likely involve pulling in an OCaml dependency.
+For example, you may want to pull in [Lwt](https://github.com/ocsigen/lwt).
+Assuming this package is available, whether you've manually downloaded it
+via [opam](https://opam.ocaml.org/) or used something like
+[esy](https://github.com/esy/esy), you'll want to let Dune know that Lwt is
+an available library.
+
+```lisp
+;; dune
+(executable
+ (name hello_reason)
+ (libraries lwt lwt.unix))
+```
+
+The modules in the Lwt package will now be globally available to your
+Reason code.
+
+```reason
+let () = {
+  Lwt_main.run(
+    Lwt_io.printf("Hello, Reason!\n")
+  );
+};
+```
+
+When Dune builds your code, it will include and compile Lwt.
+
+See a [full example
+here](https://github.com/jbranchaud/esy-reasonml-lwt-example).