Initial commit

README.md

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+# Minimal Reason native project
+
+This is the smallest possible Reason native project. To use, run
+
+```
+git clone https://github.com/aantron/reason-native-hello.git
+cd reason-native-hello
+npx esy install
+npx esy dune exec ./hello.exe
+```
+
+This will print
+
+```
+Hello, world!
+```
+
+The first time you run this, esy will take a while building all the
+dependencies. After that, esy will load the built dependencies from its cache.
+
+<br>
+<br>
+<br>
+
+## Explanation
+
+We are using four tools here:
+
+1. [**Reason**][reason] will parse our `hello.re` file for the compiler.
+2. The [**OCaml compiler**][ocaml] will translate our parsed `hello.re` into
+   native code.
+3. [**Dune**][dune] is the OCaml build system. It knows how to call into Reason
+   and OCaml in the right way to build our executable. We tell it what we want
+   in the [`dune` file][dune-file]:
+
+    ```
+    (executable
+      (name hello))
+    ```
+
+4. [**esy**][esy] is a package manager that is able to download, build, and
+   organize all of the above. Hence, [`esy.json`][esy.json] looks like this:
+
+    ```json
+    {
+      "dependencies": {
+        "@opam/dune": "^2.9",
+        "@opam/reason": "^3.7.0",
+        "ocaml": "^4.12"
+      }
+    }
+    ```
+
+    The `@opam/***` package namespace refers to the [**opam package
+    repository**](https://opam.ocaml.org/), which has a lot of useful OCaml
+    packages. However, we are not using the opam *tool* &mdash; we are using esy
+    itself to connect directly to the opam repository.
+
+    Reason libraries are also [found][npm-reason] in npm. However, many of those
+    target JavaScript &mdash; though some target both or only native code.
+
+<br>
+
+## Next steps
+
+- You can make a multi-file project by just creating another `.re` file, for
+  example `another.re`:
+
+  ```reason
+  let how_are_you =
+    "amazing!"
+  ```
+
+  You can refer to this value from `hello.re` like this:
+
+  ```reason
+  let () =
+    print_endline(Another.how_are_you)
+  ```
+
+- To depend on a library, say [Dream][dream], tell esy to download it:
+
+  ```json
+  {
+    "dependencies": {
+      "@opam/dream": "*",
+      "@opam/dune": "^2.9",
+      "@opam/reason": "^3.7.0",
+      "ocaml": "^4.12"
+    }
+  }
+  ```
+
+  and Dune to link it:
+
+  ```
+  (executable
+    (name hello)
+    (libraries dream))
+  ```
+
+- Reason can do a lot more. If you want to do full-stack Reason, meaning
+  compile Reason to both native code and JavaScript, get
+  [**ReScript**][rescript], which can compile Reason code to JS, and see the
+  [Full-stack ReScript][fullstack] example.
+
+<br>
+
+## Contact
+
+Visit the [Reason Discord][discord] and chat with us! Edits/suggestions for this
+repo are welcome. Open an issue, PR, or highlight @antron in Discord!
+
+[reason]: https://reasonml.github.io/
+[ocaml]: https://ocaml.org/
+[dune]: https://dune.build/
+[dune-file]: https://github.com/aantron/reason-native-hello/blob/master/dune
+[esy]: https://esy.sh/
+[esy.json]: https://github.com/aantron/reason-native-hello/blob/master/esy.json
+[opam]: https://opam.ocaml.org/packages/
+[npm-reason]: https://www.npmjs.com/search?q=reason
+[dream]: https://github.com/aantron/dream
+[discord]: https://discord.gg/Hrz3qKsK
+[rescript]: https://rescript-lang.org/
+[fullstack]: https://github.com/aantron/dream/tree/master/example/w-fullstack-rescript#files

dune

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+(executable
+ (name hello))

dune-project

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+(lang dune 2.9)

esy.json

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+{
+  "dependencies": {
+    "@opam/dune": "^2.9",
+    "@opam/reason": "^3.7.0",
+    "ocaml": "^4.12"
+  }
+}

hello.re

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+let () =
+  print_endline("Hello, world!");