---
layout: post
title: "Elm on FreeBSD"
date: 2019-05-11
comments: true
tags: freebsd, elm, linux
---

[Elm](https://elm-lang.org/) is a purely functional, strongly typed language for
building web-apps. I recently started playing with elm[^1] and so far love it!

There was a small bit of trouble though, Elm doesnt officially support
FreeBSD. The compiler is written in Haskell and
[couple](https://discourse.elm-lang.org/t/running-elm-on-freebsd/1613)
of
[people](https://gist.github.com/vyuh/ff05a20cb0f408e1fd0ac8c23d06025b)
have made it work on freebsd by compiling from source.

That's where I started, and soon gave up because compiling `elm 0.19`
needs `ghc-8.2.2`. That particular ghc version is no longer in binary
packages. Stack ghcs are still [broken on
FreeBSD](https://blog.dbalan.in/blog/2019/01/08/recurse-center-day-%23-2/index.html)
to try that route. All of the solutions I encountered builds ghc from
source and that was going take an eternity on my thinkpad.

Luckily elm project provides binaries for Linux - and FreeBSD
[can pretend to be
linux](https://www.freebsd.org/doc/handbook/linuxemu.html) pretty
well. Thats what I ended up doing!

1. Load the kernel module for linux emulation.

```bash
kldload linux64.ko
```

2. Get elm [linux binary from github](https://github.com/elm/compiler/releases).

```bash
wget \
 https://github.com/elm/compiler/releases/download/0.19.0/binaries-for-linux.tar.gz
tar xf binaries-for-linux.tar.gz
```

3. Then [brand the ELF
   binary](https://www.freebsd.org/cgi/man.cgi?query=brandelf&sektion=1&manpath=freebsd-release-ports)
   as type `Linux`. Kernel uses this information check decide runtime
   to use, in our case Linux emulation.

```bash
brandelf -t Linux ./elm
```

..and there we have it
```sh
$ file elm
elm: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, with debug_info, not stripped

$ ./elm
Hi, thank you for trying out Elm 0.19.0. I hope you like it!
...
```

[^1]: Shout-out to Tenor and Liz for introducing me to Elm.