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paulfioravanti's solution

to Hello World in the Elm Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

Note:

This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

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:

  • Write a function that returns the string "Hello, World!".
  • Run the test suite and make sure that it succeeds.
  • Submit your solution and check it at the website.

If everything goes well, you will be ready to fetch your first real exercise.

Elm Installation

Refer to the Exercism help page for Elm installation and learning resources.

Writing the Code

The first time you start an exercise, you'll need to ensure you have the appropriate dependencies installed.

$ elm-package install --yes

Execute the tests with:

$ elm-test

Automatically run tests again when you save changes:

$ elm-test --watch

As you work your way through the test suite, be sure to remove the skip <| calls from each test until you get them all passing!

Source

This is an exercise to introduce users to using Exercism http://en.wikipedia.org/wiki/%22Hello,_world!%22_program

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

Tests.elm

module Tests exposing (..)

import Expect
import HelloWorld exposing (helloWorld)
import Test exposing (..)


tests : Test
tests =
    describe "Hello, World!"
        [ test "Hello with no name" <|
            \() ->
                Expect.equal "Hello, World!" (helloWorld Nothing)

        -- Once you get the first test passing, remove the
        -- `skip <|` (just leave the comma) on the next two
        -- lines to continue!
        , skip <|
            test "Hello to a sample name" <|
                \() ->
                    Expect.equal "Hello, Alice!" (helloWorld (Just "Alice"))
        , skip <|
            test "Hello to another sample name" <|
                \() ->
                    Expect.equal "Hello, Bob!" (helloWorld (Just "Bob"))
        ]

elm-package.json

{
    "version": "3.0.0",
    "summary": "Exercism problems in Elm.",
    "repository": "https://github.com/exercism/elm.git",
    "license": "BSD3",
    "source-directories": [
        ".",
        ".."
    ],
    "exposed-modules": [],
    "dependencies": {
        "elm-lang/core": "5.0.0 <= v < 6.0.0",
        "elm-community/elm-test": "4.0.0 <= v < 5.0.0"
    },
    "elm-version": "0.18.0 <= v < 0.19.0"
}
module HelloWorld exposing (..)


helloWorld : Maybe String -> String
helloWorld name =
    "Hello, " ++ Maybe.withDefault "World" name ++ "!"

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