The classical introductory exercise. Just say "Hello, World!".
"Hello, World!" is the traditional first program for beginning programming in a new language or environment.
The objectives are simple:
If everything goes well, you will be ready to fetch your first real exercise.
Execute the tests with:
$ elixir hello_world_test.exs
In the test suites, all but the first test have been skipped.
Once you get a test passing, you can unskip the next one by
commenting out the relevant
@tag :pending with a
# @tag :pending test "shouting" do assert Bob.hey("WATCH OUT!") == "Whoa, chill out!" end
Or, you can enable all the tests by commenting out the
ExUnit.configure line in the test suite.
# ExUnit.configure exclude: :pending, trace: true
For more detailed information about the Elixir track, please see the help page.
This is an exercise to introduce users to using Exercism http://en.wikipedia.org/wiki/%22Hello,_world!%22_program
It's possible to submit an incomplete solution so you can see how others have completed the exercise.
if !System.get_env("EXERCISM_TEST_EXAMPLES") do Code.load_file("hello_world.exs", __DIR__) end ExUnit.start() ExUnit.configure(trace: true) defmodule HelloWorldTest do use ExUnit.Case test "says 'Hello, World!'" do assert HelloWorld.hello() == "Hello, World!" end end
defmodule HelloWorld do @moduledoc """ Elixir counts the number of arguments as part of the function name. For instance; def hello() do end would be a completely different function from def hello(name) do end Can you find a way to make all the tests pass with just one function? Hint: look into argument defaults here: http://elixir-lang.org/getting-started/modules.html#default-arguments """ @doc """ Greets the user by name, or by saying "Hello, World!" if no name is given. """ @spec hello(String.t) :: String.t def hello(name \\ "World") do "Hello, " <> name <> "!" end end
A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.
Here are some questions to help you reflect on this solution and learn the most from it.