Installing Elm on Ubuntu 14.04
Elm is a functional programming language for the web.
Elm lets you write programs in a simple functional language and it compiles to
CSS. This sounded like a cool way to learn about FRP (Functional Reactive Programming), so I decided to give it a try.
Because it’s a young language (the thesis which gave it birth was in 2012) it’s evolving fast, so dependencies and syntax are still changing.
We want to install the Elm-Platform which comes with all the tools to get started:
- elm-compiler: emm…. The compiler.
elm-make: Command line tool to turn your
- elm-reactor: This loads an interactive editor on the browser to evaluate and hot-swap code.
- elm-repl: a Read Eval Print Loop to play around with the language and explore libraries.
- elm-package: the package manager, to install/uninstall community packages.
Starting with the right version
Elm 0.15.1 you will need Haskell and Cabal (the Haskell package manager). Currently you need
GHC 7.10 and at least
However installing them with
apt-get on Ubuntu will install an older version which won’t work (
cabal 220.127.116.11 and
So the first thing is to get a more recent version of Cabal and ghc
sudo add-apt-repository ppa:hvr/ghc sudo apt-get update
The packages install into
/opt/ghc/$VER/so in order to use them, the easiest way is to bring a particular GHC version into scope by placing the respective
/opt/ghc/$VER/binfolder early into the
PATHenvironment variable. See also https://github.com/hvr/multi-ghc-travis for more information
sudo apt-get install ghc-7.10.1 sudo apt-get install cabal-install-1.22
and add it to your
PATH variable (or add it to your .bashrc):
# Haskell & cabal Path export PATH=/opt/ghc/7.10.1/bin:$PATH export PATH=/opt/cabal/1.22/bin:$PATH
You should now see:
cabal --version cabal-install version 18.104.22.168 using version 22.214.171.124 of the Cabal library
which cabal /opt/cabal/1.22/bin/cabal
The Elm Platform
- chose a directory to save all the files for your installation (but don’t create a directory). Let’s assume we want it to live at
~/Documents/code/(You should not move this directory after it is created, so choose carefully before progressing)
- add the absolute path
PATH. For our example above, this would be:
$ export PATH=/home/user/Documents/code/Elm-Platform/0.15.1/.cabal-sandbox/bin:$PATH
or you can add it to .bashrc or .bash_profile as described here.
- Let’s go to the directory we selected (in our example
$ cd ~/Documents/code), and run the haskell installation file:
# if you are on windows, or some other place without curl, just download this file manually curl https://raw.githubusercontent.com/elm-lang/elm-platform/master/installers/BuildFromSource.hs > BuildFromSource.hs runhaskell BuildFromSource.hs 0.15.1
You can test if your installed version is right with:
$ elm-make --help elm-make 0.2 (Elm Platform 0.15.1)
$ which elm-make /home/user/Documentos/code/Elm-Platform/0.15.1/.cabal-sandbox/bin/elm-make
Let’s try it out:
let’s create a new directory,
mkdir helloworld && cd helloworld and create a
-- helloworld.elm import Html exposing (text) main = text "Hello, World!"
you can compile it with
elm-make which should create 3 files:
and check out the result in the browser with:
elm-reactor Elm Reactor 0.3.2 (Elm Platform 0.15.1) Listening on http://0.0.0.0:8000/