Exercism Erlang Track

Exercism exercises in Erlang

Contributing guide

For general information about how exercism works, please see the contributing guide.

If you create “claiming” PRs with obviously unfinished code, please provide an estimate in the PR description when you will continue to work on the PR or you think it will be finished.

Setting up your system for local development on the track

Please make sure you have installed erlang/OTP and rebar3 as described on Installing Erlang or docs/INSTALLATION.md in this repository. Also run bin/fetch-configlet to download the JSON-checker.

Please make sure you use one of the releases of erlang/OTP as specified in .travis.yml, as these are the ones officially tested and supported by this track.

Feel free to use any feature that was introduced in the oldest version of the range, while also avoiding everything that has been removed or deprecated in the newest one.

Implementing an exercise

When there is a mention of “slug-name” it refers to the slug as used on exercism URLs, “erlangified_slug_name” does mean, that you have to replace dashes (-) in the slug by underscores (_) to make them compatible with erlang syntax.

1. Create a folder exercises/<slug-name>
2. Set up folder structure (include, src, and test).
3. Copy rebar.conf, src/*.app.src, and include/exercism.hrl from another exercise. 3.1. Find the line {eunit_tests, [{application, <erlangified_slug_name>}]} in rebar.conf and alter it to match the current exercise. 3.2. Rename src/*.app.src to src/<erlangified_slug_name>. 3.3. Change the old erlangified_slug_name on the first line to the new one. 3.4. Change the old slug-name on the second line to the new one. 3.5. Leave include/exercism.hrl untouched.
4. Create a testfile/-module in test-folder. It is preferred to name it after the erlangified_slug_name and insert the boilerplate code shown below.
5. Implement your example in src/example.erl and use example as the name for the module.
6. Add tests. Make sure you are using the macro ?TESTED_MODULE when referencing the students module.
7. Run tests using rebar3 eunit.

Repeat steps 5., 6., and 7. until all tests are implemented and your solution passes all tests.

If there is a exercises/<slug-name>/canonical-data.json in problem-specifications, make sure to implement your tests and examples in a way that the canonical data is integrated and not violated.

You may add further tests, as long as they do not violate canonical data and add value to the exercise or are necessary for erlang specific things.

Also please make sure to add a HINTS.md with some hints for the students if the exercise becomes tricky or might not be obvious.

-module(<test module name>).

-define(TESTED_MODULE, (sut(<erlangified_slug_name>))).
-define(TEST_VERSION, 1).
-include("exercism.hrl").

Before pushing

Please make sure, that all tests pass by running _test/check-exercises.escript. On windows you might need to call escript _test/check-exercises.escript. Also a run of bin/configlet should pass without error message.

Both programs will be run on Travis and a merge is unlikely when tests fail.