Before the course begins
Hello! We are glad you are here. Let’s get you set up for the workshop.


You will need
a laptop computer;
a web browser:
Mozilla Firefox
Google Chrome
During the workshop you will learn how to write and publish a computer program running in a web browser. Computer Programs are represented as text, so the text editor is the most fundamental tool of a programmer. We are going to use the Elm live editor called Ellie. It’s free to use and requires no registration. All you need to do to write and run our code is open this address:
On Ellie, you write your codes on the left side (in the dark area of the screen) and the result is displayed on the right side (white area of the screen). The dark area is divided in two parts:
. During the workshop we will only modify the Elm code. You can use small downward arrow
to hide the HTML part and get some more space for your Elm code.
When you open Ellie there will already be some code in Elm part. You don’t need it so please delete it. We will write our own code together.
On the top left side of the screen there are two buttons:
is for installing packages and
is for adjusting settings. On the top right side of the dark area of the screen there is
button. We can use to format our code (make it look pretty). After finishing writing a code we click
(on the top right side of the white area). This will run and display our program.
Go to
to give your project a name. Insert any name you wish. To save your work first click
and then bookmark it in your browser.

Our First Program!

First we are going to create a very simple program that just writes “Hello Tree” on the screen. Write the code as shown below in the Elm part of the Ellie app.
module Main exposing (main)
import Html
main =
Html.text "Hello, Tree"
to make sure it’s formatted nicely and then
. You should see something like this:
Hello, Tree!
Did it work? Congratulations!
You are all set and ready for
Day 1
Got questions? Got Stuck?
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