exercism / raku

Exercism exercises in Raku

Exercism Raku Track

Exercism exercises in Raku

Contributing Guide

Please see the contributing guide.

Code of Conduct

Help us keep Exercism welcoming. Please read and abide by the Code of Conduct.

Adding and Updating Exercises

Please use exercise-gen.raku in the bin/ directory when either adding or updating an exercise. The bin/ directory contains a README.md with information on how to use the generator.

When adding a new exercise, ensure that the exercise is included in the exercises array in config.json.

Running The Tests

Run prove -re raku exercises/practice/*/.meta/solutions/ to run all exercise tests.

Raku icon

The Raku "Camelia" logo is owned by Larry Wall and is released under version 2.0 of the Artistic License. We are using it to identify the Raku language itself, not any part of Exercism, which we believe to be admissible under fair use. The version of the logo that we are using is an adaptation of the logo found on https://en.wikipedia.org/wiki/Raku_(programming_language).

raku's Issues

Move exercises to subdirectory

The problems api (x-api) now supports having exercises collected in a subdirectory
named exercises.

That is to say that instead of having a mix of bin, docs, and individual exercises,
we can have bin, docs, and exercises in the root of the repository, and all
the exercises collected in a subdirectory.

In other words, instead of this:

x{TRACK_ID}/
├── LICENSE
├── README.md
├── bin
│   └── fetch-configlet
├── bowling
│   ├── bowling_test.ext
│   └── example.ext
├── clock
│   ├── clock_test.ext
│   └── example.ext
├── config.json
└── docs
│   ├── ABOUT.md
│   └── img
... etc

we can have something like this:

x{TRACK_ID}/
├── LICENSE
├── README.md
├── bin
│   └── fetch-configlet
├── config.json
├── docs
│   ├── ABOUT.md
│   └── img
├── exercises
│   ├── bowling
│   │   ├── bowling_test.ext
│   │   └── example.ext
│   └── clock
│       ├── clock_test.ext
│       └── example.ext
... etc

This has already been deployed to production, so it's safe to make this change whenever you have time.

Build Representer and Analyzer

This issue is part of the migration to v3. You can read full details about the various changes here.

Representer

In Exercism v3, we're introducing a new (optional) tool: the representer. The goal of the representer is to take a solution and returning a representation, which is an extraction of a solution to its essence with normalized names, comments, spacing, etc. but still uniquely identifying the approach taken. Two different ways of solving the same exercise must not have the same representation.

Each representer is track-specific. When a new solution is submitted, we run the track's representer, which outputs two JSON files that describe the representation.

Once we have a normalized representation for a solution, a team of vetted mentors will look at the solution and comment on it (if needed). These comments will then automatically be submitted to each new solution with the same representation. A notification will be sent for old solutions with a matching representation.

Each track should build a representer according to the spec. For tracks building a representer from scratch, we have a starting guide.

The representer is an optional tool though, which means that if a track does not have a representer, it will still function normally.

Analyzer

In Exercism v3, we are making increased use of our v2 analyzers. Analyzers automatically assess student's submissions and provide mentor-style commentary. They can be used to catch common mistakes and/or do complex solution analysis that can't easily be done directly in a test suite.

Each analyzer is track-specific. When a new solution is submitted, we run the track's analyzer, which outputs a JSON file that contains the analysis results.

In v2, analyzer comments were given to a mentor to pass to a student. In v3, the analyzers will normally output directly to students, although we have added an extra key to output suggestions to mentors. If your track already has an analyzer, the only requisite change is updating the outputted copy to be student-facing.

Each track should build an analyzer according to the spec. For tracks building an analyzer from scratch, we have a starting guide.

The analyzer is an optional tool though, which means that if a track does not have an analyzer, it will still function normally.

Goal 1

Build a representer for your track according to the spec. Check this page to help you get started with building a representer.

Note that the simplest representer is one that merely returns the solution's source code.

It can be very useful to check how other tracks have implemented their representer.

Goal 2

Build an analyzer for your track according to the spec. Check this page to help you get started with building an analyzer.

It can be very useful to check how other tracks have implemented their analyzer.

Choosing between representer and analyzer

If you want to build both, we recommend starting by building the representer for the following reasons:

• Representers are usually (far) easier to implement
• Representers can have a far bigger impact on the mentoring load than analyzers by empowering mentors
• Representers apply to all exercises, whereas analyzers usually target specific exercises or a subset

Tracking

exercism/v3-launch#8

Create a getting started page for perl6

There's one for Perl5 already: https://github.com/exercism/docs/blob/master/app/pages/languages/getting-started-with-perl5.md

Moving from Travis to GitHub Actions

Hello 🙂

Over the last few months we've been transferring all our CI from Travis to GitHub Actions (GHA). We've found that GHA are easier to work with, more reliable, and much much faster.

Based on our success with GHA and increasing intermittent failures on Travis, we have now decided to try and remove Travis from Exercism's org altogether and shift everything to GHA. This issue acts as a call to action if your track is still using Travis.

For most CI checks this should be a transposing from Travis' syntax to GHA syntax, and hopefully quite straightforward (see this PR for an example). However, if you do encounter any issues doing this, please ask on Slack where lots of us now have experience with GHA, or post a comment here and I'll tag relevant people. This would also make a good Hacktoberfest issue for anyone interested in making their first contribution 🙂

If you've already switched this track to GHA, please feel free to close this issue and ignore it.

Thanks!

Copy track icon into language track repository

Right now all of the icons used for the language tracks (which can be seen at http://exercism.io/languages) are stored in the exercism/exercism.io repository in public/img/tracks/. It would make a lot more sense to keep these images along with all of the other language-specific stuff in each individual language track repository.

There's a pull request that is adding support for serving up the track icon from the x-api, which deals with language-specific stuff.

In order to support this change, each track will need to

• create a directory named img/ at the root of this repository if it doesn't already exist, then
• find the correct icon in https://github.com/exercism/exercism.io/tree/master/public/img/tracks, and
• stick it in the img/ directory, and importantly
• name the image icon.png

In other words, at the end of it you should have the following file:

./img/icon.png

See exercism/exercism#2925 for more details.

[v3] Is there any way I can help on raku track?

Delete configlet binaries from history?

I made a really stupid choice a while back to commit the cross-compiled
binaries for configlet (the tool that sanity-checks the config.json
against the implemented problems) into the repository itself.

Those binaries are HUGE, and every time they change the entire 4 or 5 megs get
recommitted. This means that cloning the repository takes a ridiculously long
time.

I've added a script that can be run on travis to grab the latest release from
the configlet repository (bin/fetch-configlet), and travis is set up to run
this now instead of using the committed binary.

I would really like to thoroughly delete the binaries from the entire git
history, but this will break all the existing clones and forks.

The commands I would run are:

# ensure this happens on an up-to-date master
git checkout master && git fetch origin && git reset --hard origin/master

# delete from history
git filter-branch --index-filter 'git rm -r --cached --ignore-unmatch bin/configlet-*' --prune-empty

# clean up
rm -rf .git/refs/original/
git reflog expire --all
git gc --aggressive --prune

# push up the new master, force override existing master branch
git push -fu origin master

If we do this everyone who has a fork will need to make sure that their master
is reset to the new upstream master:

git checkout master
git fetch upstream master
git reset --hard upstream/master
git push -fu origin master

We can at-mention (@) all the contributors and everyone who has a fork here in this
issue if we decide to do it.

The important question though, is: Is it worth doing?

Do you have any other suggestions of how to make sure this doesn't confuse people and break their
repository if we do proceed with this change?

Create generator for tests

This will have the advantage of directly using the canonical data in x-common.

An example of doing this can be found with the Go and Ruby tracks.

Go executable
Go test helper

ruby generate executable
ruby generate library
Sample test cases handler

Update status of track

This issue is part of the migration to v3. You can read full details about the various changes here.

There are several new features in Exercism v3 for tracks to build. To selectively enable these features on the Exercism v3 website, each track must keep track of the status of the following features:

• Concept Exercises have been built
• A test runner has been implemented
• A representer has been implemented
• An analyzer has been implemented

The status of these features is specified in the top-level "status" field in the track's config.json, as specified in the spec.

Goal

The "status" field in the config.json file should be updated to indicate the status of the features for this track. The list of features is defined in the spec.

Example

{
  "status": {
    "concept_exercises": true,
    "test_runner": true,
    "representer": false,
    "analyzer": false
  }
}

Tracking

exercism/v3-launch#12

[v3] Add tags

This issue is part of the migration to v3. You can read full details about the various changes here.

In Exercism v3, tracks can be annotated with tags. This allows searching for tracks with a certain tag combination, making it easy for students to find an interesting track to join.

Tags are specified in the top-level "tags" field in the track's config.json file and are defined as an array of strings, as specified in the spec.

Goal

The "tags" field in the config.json file should be updated to contain the tags that are relevant to this track. The list of tags that can be used is listed in the spec.

Example

{
  "tags": [
    "runtime/jvm",
    "platform/windows",
    "platform/linux",
    "paradigm/declarative",
    "paradigm/functional",
    "paradigm/object_oriented"
  ]
}

Tracking

exercism/v3-launch#1

Evaluate our use of `plan` and `done-testing`

As I am not very fond of telling people how to do things, nor am I in any sort of position to do so(!) I would like to have a discussion as to how we should go forward with the use of plan and done-testing in tests, and hopefully we can decide on a standard way of using them.

In my opinion:

1. We should not include done-testing.
   plan already results in done-testing running. If done-testing is left in, and somebody removes plan (e.g. they remove it while modifying a test, but forget to put it back in), Travis will not catch it and will report success. It might not happen, but it is a possibility. In the Perl 6 documentation it is also recommended that it be removed: https://docs.perl6.org/language/testing#Test_plans

2. plan should use a hardcoded value.
   Similar to the above. If someone accidentally removes a test, and it is missed in a review, Travis will not catch it and report success. Again, it might not happen in future, but it has happened in the past. (And that is the story of how I ended up on this repository!).

3. subtests should also each have a plan, as without one it behaves similarly as if done-testing had been used.

TL;DR Give Travis the capacity to catch out mistakes we make.

Does anyone have any disagreements with my opinions, or any suggestions otherwise? 🙂

[Important] The current website is about to enter maintenance mode to aid with v3 launch

TL;DR; At the end of Jan 2021, all tracks will enter v3 staging mode. Updates will no longer sync with the current live website, but instead sync with the staging website. The Raku section of the v3 repo will be extracted and PR'd into this track (if appropriate). Further issues and information will follow over the coming weeks to prepare Raku for the launch of v3.

Over the last 12 months, we've all been hard at work developing Exercism v3. Up until this point, all v3 tracks have been under development in a single repository - the v3 repository. As we get close to launch, it is time for us to explode that monorepo back into the normal track repos. Therefore, at the end of this month (January 2021), we will copy the v3 tracks contents from the v3 repository back to the corresponding track repositories.

As v3 tracks are structured differently than v2 tracks, the current (v2) website cannot work with v3 tracks. To prevent the v2 website from breaking, we'll disable syncing between track repositories and the website. This will effectively put v2 in maintenance mode, where any changes in the track repos won't show up on the website. This will then allow tracks to work on preparing for the Exercism v3 launch.

Where possible, we will script the changes needed to prepare tracks for v3. For any manual changes that need to be happening, we will create issues on the corresponding track repositories. We will be providing lots of extra information about this in the coming weeks.

We're really excited to enter the next phase of building Exercism v3, and to finally get it launched! 🙂

Verify contents and format of track documentation

Each language track has documentation in the docs/ directory, which gets included on the site
on each track-specific set of pages under /languages.

We've added some general guidelines about how we'd like the track to be documented in exercism/exercism#3315
which can be found at https://github.com/exercism/exercism.io/blob/master/docs/writing-track-documentation.md

Please take a moment to look through the documentation about documentation, and make sure that
the track is following these guidelines. Pay particularly close attention to how to use images
in the markdown files.

Lastly, if you find that the guidelines are confusing or missing important details, then a pull request
would be greatly appreciated.

Add helpful information to the SETUP.md

The contents of the SETUP.md file gets included in
the README.md that gets delivered when a user runs the exercism fetch
command from their terminal.

At the very minimum, it should contain a link to the relevant
language-specific documentation on
help.exercism.io.

It would also be useful to explain in a generic way how to run the tests.
Remember that this file will be included with all the problems, so it gets
confusing if we refer to specific problems or files.

Some languages have very particular needs in terms of the solution: nested
directories, specific files, etc. If this is the case here, then it would be
useful to explain what is expected.

---

Thanks, @tejasbubane for suggesting that we add this documentation everywhere.
See exercism.io#2198.

Include a "How to run tests" section in the readme file

For example, include something like

## Running tests

Execute the tests with:


$ perl6 test.t


or if you want pretty colours


$ prove -e 'perl6' -vlr test.t

Ensure Perl 6 track is ready for v2 launch

There are a number of things we're going to want to check before the v2 site goes live. There are notes below that flesh out all the checklist items.

• The track has a page on the v2 site: https://v2.exercism.io/tracks/perl6
• The track page has a short description under the name (not starting with TODO)
• The "About" section is a friendly, colloquial, compelling introduction
• The "About" section follows the formatting guidelines
• The code example gives a good taste of the language and fits within the boundaries of the background image
• There are exercises marked as core
• Exercises have rough estimates of difficulty
• Exercises have topics associated with them
• The first exercise is auto_approve: true

Track landing page

The v2 site has a landing page for each track, which should make people want to join it. If the track page is missing, ping @kytrinyx to get it added.

Blurb

If the header of the page starts with TODO, then submit a pull request to https://github.com/exercism/perl6/blob/master/config.json with a blurb key. Remember to get configlet and run configlet fmt . from the root of the track before submitting.

About section

If the "About" section feels a bit dry, then submit a pull request to https://github.com/exercism/perl6/blob/master/docs/ABOUT.md with suggested tweaks.

Formatting guidelines

In order to work well with the design of the new site, we're restricting the formatting of the ABOUT.md. It can use:

• Bold
• Italics
• Links
• Bullet lists
• Number lists

Additionally:

• Each sentence should be on its own line
• Paragraphs should be separated by an empty line
• Explicit <br/> can be used to split a paragraph into lines without spacing between them, however this is discouraged.

Code example

If the code example is too short or too wide or too long or too uninteresting, submit a pull request to https://github.com/exercism/ocaml/blob/master/docs/SNIPPET.txt with a suggested replacement.

Exercise metadata

Where the v1 site has a long, linear list of exercises, the v2 site has organized exercises into a small set of required exercises ("core").

If you update the track config, remember to get configlet and run configlet fmt . from the root of the track before submitting.

Topic and difficulty

Core exercises unlock optional additional exercises, which can be filtered by topic an difficulty, however that will only work if we add topics and difficulties to the exercises in the track config, which is in https://github.com/exercism/perl6/blob/master/config.json

Auto-approval

We've currently made any hello-world exercises auto-approved in the backend of v2. This means that you don't need mentor approval in order to move forward when you've completed that exercise.

Not all tracks have a hello-world, and some tracks might want to auto approve other (or additional) exercises.

Track mentors

There are no bullet points for this one :)

As we move towards the launch of the new version of Exercism we are going to be ramping up on actively recruiting people to help provide feedback. Our goal is to get to 100%: everyone who submits a solution and wants feedback should get feedback. Good feedback.

If you're interested in helping mentor the track, check out http://mentoring.exercism.io/

When all of the boxes are ticked off, please close the issue.

Tracking progress in exercism/meta#104

Add prerequisites to Practice Exercises

This issue is part of the migration to v3. You can read full details about the various changes here.

Exercism v3 introduces a new type of exercise: Concept Exercises. All existing (V2) exercises will become Practice Exercises.

Concept Exercises and Practice Exercises are linked to each other via Concepts. Concepts are taught by Concept Exercises and practiced in Practice Exercises. Each Exercise (Concept or Practice) has prerequisites, which must be met to unlock an Exercise - once all the prerequisite Concepts have been "taught" by a Concept Exercise, the exercise itself becomes unlocked.

For example, in some languages completing the Concept Exercises that teach the "String Interpolation" and "Optional Parameters" concepts might then unlock the two-fer Practice Exercise.

Each Practice Exercise has two fields containing concepts: a practices field and a prerequisites field.

Practices

The practices key should list the slugs of Concepts that this Practice Exercise actively allows a student to practice.

• These show up in the UI as "Practice this Concept in: TwoFer, Leap, etc"
• Try and choose 3 - 8 Exercises that practice each Concept.
• Try and choose at least two Exercises that allow someone to practice the basics of a Concept.
• Some Concepts are very common (for example strings). In those cases we recommend choosing a few good exercises that make people think about those Concepts in interesting ways. For example, exercises that require UTF-8, string concatenation, char enumeration, etc, would all be good examples.
• There should be one or more Concepts to practice per exercise.

Prerequisites

The prerequisites key lists the Concept Exercises that a student must have completed in order to access this Practice Exercise.

• These show up in the UI as "Learn Strings to unlock TwoFer"
• It should include all Concepts that a student needs to have covered to be able to complete the exercise in at least one idiomatic way. For example, for the TwoFer exercise in Ruby, prerequisites might include strings, optional-params, implicit-return.
• For Exercises that can be completed using alternative Concepts (e.g. an Exercise solvable by loops or recursion), the maintainer should choose the one approach that they would like to unlock the Exercise, considering the student's journey through the track. For example, the loops/recursion example, they might think this exercise is a good early practice of loops or that they might like to leave it later to teach recursion. They can also make use of an analyzer to prompt the student to try an alternative approach: "Nice work on solving this via loops. You might also like to try solving this using Recursion."
• There should be one or more prerequisites Concepts per exercise.

Although ideally all Concepts should be taught by Concept Exercises, we recognise that it will take time for tracks to achieve that. Any Practice Exercises that have prerequisites which are not taught by Concept Exercises, will become unlocked once the final Concept Exercise has been completed.

Goal

Practices

The "practices" field of each element in the "exercises.practice" field in the config.json file should be updated to contain the practice concepts. See the spec.

To help with identifying the practice concepts, the "topics" field can be used (if it has any contents). Once prerequisites have been defined for a Practice Exercise, the "topics" field should be removed.

Each practice concept should have its own entry in the top-level "concepts" array. See the spec.

Prerequisites

The "prerequisites" field of each element in the "exercises.practice" field in the config.json file should be updated to contain the prerequisite concepts. See the spec.

To help with identifying the prerequisites, the "topics" field can be used (if it has any contents). Once prerequisites have been defined for a Practice Exercise, the "topics" field should be removed.

Each prerequisite concept should have its own entry in the top-level "concepts" array. See the spec.

Example

{
  "exercises": {
    "practice": [
      {
        "uuid": "8ba15933-29a2-49b1-a9ce-70474bad3007",
        "slug": "leap",
        "name": "Leap",
        "practices": ["if-statements", "numbers", "operator-precedence"],
        "prerequisites": ["if-statements", "numbers"],
        "difficulty": 1
      }
    ]
  }
}

Tracking

exercism/v3-launch#6

Investigate track health and status of the track

I've used Sarah Sharp's FOSS Heartbeat project to generate stats for each of the language track repositories, as well as the x-common repository.

The Exercism heartbeat data is published here: https://exercism.github.io/heartbeat/

When looking at the data, please disregard any activity from me (kytrinyx), as I would like to get the language tracks to a point where they are entirely maintained by the community.

Please take a look at the heartbeat data for this track, and answer the following questions:

• To what degree is the track maintained?
• Who (if anyone) is merging pull requests?
• Who (if anyone) is reviewing pull requests?
• Is there someone who is not merging pull requests, but who comments on issues and pull requests, has thoughtful feedback, and is generally helpful? If so, maybe we can invite them to be a maintainer on the track.

I've made up the following scale:

• ORPHANED - Nobody (other than me) has merged anything in the past year.
• ENDANGERED - Somewhere between ORPHANED and AT RISK.
• AT RISK - Two people (other than me) are actively discussing issues and reviewing and merging pull requests.
• MAINTAINED - Three or more people (other than me) are actively discussing issues and reviewing and merging pull requests.

It would also be useful to know if there a lot of activity on the track, or just the occasional issue or comment.

Please report the current status of the track, including your best guess on the above scale, back to the top-level issue in the discussions repository: exercism/discussions#97

Recruiting additional maintainers for Raku

We're about to start a big push towards version 3 (v3) of Exercism. This is going to be a really exciting step forward for Exercism, with in-browser coding, new Concept Exercises with automated feedback, improved mentoring and much more.

This to be a big community effort, with the work spread out among hundreds of volunteers across Exercism. One key thing is going to be each track having enough maintainers who have the time to manage that community effort. We are therefore putting out a call for new maintainers to bolster our numbers. We're hoping that our existing maintainers will be able to act as mentors to the newer maintainers we add, and take on a parental role in the tracks.

If you are an existing maintainer, could you please reply to this letting us know that you think you'll have time (2-3hrs/week) to help with this over the next 6 months. If you won't have that time, but still want to be a maintainer and just help where you can instead, please tell us that too. If you have come to the end of the road as a maintainer, then we totally understand that and appreciate all your effort, so just let us know.

For anyone new who's interested in becoming a maintainer, thanks for your interest! Being an Exercism maintainer is also a great opportunity to work with some other smart people, learn more about your language of choice, and gain useful skills and experience that are useful for growing your career in the technical leadership direction. Please write a comment below introducing yourself along with your Exercism handle, and telling us why you're interested in becoming a maintainer, and any relevant experience. We will then evaluate every application and contact you using your exercism email address once we have finished the evaluation process.

Thank you!

See also exercism/exercism#5161

Exercises are too hard too use

From what I understand the exercises fetch only the test file and the readme and are missing the module file.

For beginners, it's very confusing how to write the code to solve the challenge.

Please include more files/instructions for beginners who don't necessarily know what a module is.

Update docs/TESTS.md to line up with SETUP.md

The instructions aren't currently in line with SETUP.md so I'd like to make some improvements for consistency.

What was it like to learn Perl 6?

We’ve recently started a project to find the best way to design our tracks, in order to optimize the learning experience of students.

As a first step, we’ll be examining the ways in which languages are unique and the ways in which they are similar. For this, we’d really like to use the knowledge of everyone involved in the Exercism community (students, mentors, maintainers) to answer the following questions:

1. How was your experience learning Perl 6? What was helpful while learning Perl 6? What did you struggle with? How did you tackle problems?
2. In what ways did Perl 6 differ from other languages you knew at the time? What was hard to learn? What did you have to unlearn? What syntax did you have to remap? What concepts carried over nicely?

Could you spare 5 minutes to help us by answering these questions? It would greatly help us improve the experience students have learning Perl 6 :)

Note: this issue is not meant as a discussion, just as a place for people to post their own, personal experiences.

Want to keep your thoughts private but still help? Feel free to email me at [email protected]

Thank you!

Pass linting checks

This issue is part of the migration to v3. You can read full details about the various changes here.

The configlet tool has a lint command that checks if a track's configuration files are properly structured - both syntactically and semantically. Misconfigured tracks may not sync correctly, may look wrong on the website, or may present a suboptimal user experience, so configlet's guards play an important part in maintaining the integrity of Exercism.

We're updating configlet to work with v3 tracks, which have a different set of requirements than v2 tracks.

The full list of rules that will be checked by the linter can be found in this spec.

⚠ Note that only a subset of the linting rules has been implemented at this moment. This means that while your track may be passing the checks at this moment, it might fail later. We thus strongly suggest you keep this issue open until we let you know otherwise.

Goal

Ensure that the track passes all the (v3 track) checks defined in configlet lint.

To help verify that the track passes all the linting rules, the v3 preparation PR has added a GitHub Actions workflow that automatically runs configlet lint.

It is also possible to run configlet lint locally by running the ./bin/fetch-configlet (or ./bin/fetch-configlet.ps1) script to download a local copy of the configlet binary. Once downloaded, you can then do ./bin/configlet lint to run the linting on your own machine.

Tracking

exercism/v3-launch#3

Implement Perl 6 exercises

Copied from exercism/exercism#1028

• bob
• rna-transcription
• word-count
• anagram
• beer-song
• nucleotide-count
• point-mutations
• phone-number
• grade-school
• robot-name
• etl
• leap
• space-age
• grains
• gigasecond
• triangle
• scrabble-score
• roman-numerals
• binary
• prime-factors
• raindrops

Add Perl 6 syntax highlighting on exercism.io

Currently, there is no highlighting for Perl 6 code on exercism.io. It appears that exercism.io is using Rouge:
https://github.com/exercism/exercism.io/blob/master/lib/exercism/syntax_highlighter.rb

Perhaps it would be possible to port from pygments to Rouge?

Change track name to Raku

As of October 2019, Perl 6 has officially been renamed Raku.

https://github.com/perl6/problem-solving/blob/master/solutions/language/Path-to-Raku.md

Link to Gitter room no longer works

Either the URL needs to be changed back to xperl, or the room itself needs to be renamed. Is the latter doable?

Create stub files for all exercises

We have decided to require all file-based tracks to provide stubs for their exercises.

The lack of stub file generates an unnecessary pain point within Exercism, contributing a significant proportion of support requests, making things more complex for our students, and hindering our ability to automatically run test-suites and provide automated analysis of solutions.

We believe that it’s essential to understand error messages, know how to use an IDE, and create files. However, getting this right as you’re just getting used to a language can be a frustrating distraction, as it can often require a lot of knowledge that tends to seep in over time. At the start, it can be challenging to google for all of these details: what file extension to use, what needs to be included, etc. Getting people up to speed with these things are not Exercism’s focus, and we’ve decided that we are better served by removing this source of confusion, letting people get on with actually solving the exercises.

The original discussion for this is at exercism/discussions#238.

Therefore, we’d like this track to provide a stub file for each exercise.

• If this track already provides stub files for all exercises, please close this issue.
• If this track already has an open issue for creating stubs, then my apologies. Please close one as a duplicate.
• Otherwise, please respond to this issue with useful details about what needs to be done to complete this task in this track so that people who are not familiar with the track may easily contribute.

scrabble-score: replace 'multibillionaire' with 'oxyphenbutazone'

The word multibillionaire is too long for the scrabble board. Oxyphenbutazone, on the other hand, is legal.

Please verify that there is no test for multibillionaire in the scrabble-score in this track. If the word is included in the test data, then it should be replaced with oxyphenbutazone. Remember to check the case (if the original is uppercase, then the replacement also should be).

If multibillionaire isn't used, then this issue can safely be closed.

See exercism/problem-specifications#86

[v3] Configure online editor

This issue is part of the migration to v3. You can read full details about the various changes here.

In Exercism v3, students can now choose to work on exercises directly from their browser, instead of having to download exercises to their local machine. The track-specific settings for the in-browser editor are defined in the top-level "online_editor" field in the track's config.json file. This field is defined as an object with two fields:

• "indent_style": the indent style, either "space" or "tab".
• "indent_size": the indent size, which is an integer (e.g. 4).

You can find a full description of these fields in the spec.

Goal

The "online_editor" field should be updated to correspond to the track's best practices regarding indentation.

Example

"online_editor": {
  "indent_style": "space",
  "indent_size": 4
}

Tracking

exercism/v3-launch#2

Override probot/stale defaults, if necessary

Per the discussion in exercism/discussions#128 we
will be installing the probot/stale integration on the Exercism organization on
April 10th, 2017.

By default, probot will comment on issues that are older than 60 days, warning
that they are stale. If there is no movement in 7 days, the bot will close the issue.
By default, anything with the labels security or pinned will not be closed by
probot.

If you wish to override these settings, create a .github/stale.yml file as described
in https://github.com/probot/stale#usage, and make sure that it is merged
before April 10th.

If the defaults are fine for this repository, then there is nothing further to do.
You may close this issue.

Remove obsolete version tracking assertions in exercises

Some tracks have added assertions to the exercise test suites that ensure that the solution has a hard-coded version in it.
In the old version of the site, this was useful, as it let commenters see what version of the test suite the code had been written against, and they wouldn't accidentally tell people that their code was wrong, when really the world had just moved on since it was submitted.

If this track does not have any assertions that track versions in the exercise tests, please close this issue.

If this track does have this bookkeeping code, then please remove it from all the exercises.

See exercism/exercism#4266 for the full explanation of this change.

Review request

Hello @exercism/reviewers,

The Raku repository has a large number of pull requests that require reviews. Almost all of them are JSON changes via the exercise generator, with very little Raku code changes, so I'm hoping they'll all be fairly straightforward!

Recommend a linter for Perl?

This may or may not be appropriate in this language. See exercism/docs#54 for details.

Update ABOUT.md so that it complies with meta#85

Re: exercism/meta#85

In summary, ABOUT.md should now only use:

• Bold
• Italics
• Links
• Bullet lists
• Number lists
• Each sentence should be on its own line
• Paragraphs separated by an empty line
• Explicit
  used to split a paragraph into lines without spacing between them (discouraged).

Launch Checklist

Launch Checklist

Step 0: Prep the Repo (@kytrinyx)

• Create the repository
• Create starter issues
• Turn on Travis CI for the track

Step 1: Implement Exercises

• Implement at least 10 problems

See the contributing guide for the details about the format of an exercise.

The short version is:

• a test suite
• an example solution, named with example (case-insensitive) in the filename
• a section in the "exercises" key of the config.json file with the slug, topics, and difficulty level.

The topics can be an empty list, and the difficulty level is from 1 to 10, and can default to 1 until we know more about the exercises.

"exercises": [
  {
    "slug": "hello-world" ,
    "difficulty": 1,
    "topics": []
  }
]

Step 2: Add the Track to Exercism (@kytrinyx)

• Add Perl 6 as a submodule in trackler
• Update x-api and deploy

This means that it will show up on http://exercism.io/languages and http://exercism.io/languages/perl6

Step 3: Make the Track Ready for Launch

• Define test_pattern in config.json
• Add a language icon or logo + attribution (MISSING ATTRIBUTION)
• Write documentation
• Find track mentors
• Add track mentors on the site (@kytrinyx)

test_pattern

The exercism.io website links to the exercise implementations, so it needs to know how to recognize the filename(s) for the test suite.

The "test_pattern" value in the config.json file should be a string that can be compiled as a regular expression, and which will match on the file or files that comprise the test suite of an exercise.

If the test filenames contain the word "test" (case insensitive) then the "test_pattern" key can be deleted.

Language Icon and Attribution

We try to create a language icon that has the exercism colors, and is recognizably similar to the language icon. Sometimes this isn't possible due to copyright issues.

The Exercism colors are:

• #D81D4E (pink)
• #212121 (charcoal)

The icon is used throughout the site in order to identify the language track, and to identify code that has been submitted to that track.

See http://exercism.io/languages for all the existing icons.

Icon

If image assets are not your strong suit, just find a reasonable image to start from, along with the information about the licensing, and we'll figure out the colorization thing (I've written some scripts to help me do this part).

The logo should be named icon.png and live under img/ in this repository. If you know how, go ahead and make an SVG as well.

Attribution

The attribution goes in the README.md file.

If the icon we have based this on is not in the public domain, we need to provide information about license and provenance. If we require permission to use and/or change the icon, then we need to obtain that permission before we can use it.

Documentation

The documentation is used in the http://exercism.io/languages/perl6 section to help people get started with the track.

The files live in the docs/ directory here in this repository, and gets served to the site via the x-api. It should contain at minimum:

• INSTALLATION.md - about how to get the language set up locally.
• TESTS.md - about how to run the tests for the exercises.

Some nice to haves:

• ABOUT.md - a short, friendly blurb about the language. What types of problems does it solve really well? What is it typically used for?
• LEARNING.md - a few notes about where people might want to go to learn the language from scratch.
• RESOURCES.md - references and other useful resources.

Find Track Mentors

Usually in order to see someone's solution you have to have submitted the exercise yourself. Track mentors can access all of the solutions in a given language. Track mentors can therefore help review solutions that people submit on the website in the beginning when few people have submitted solutions to exercises.

Ideally we should have a handful of people who are willing to check Exercism regularly to give people feedback, in order to start the track off on the right note.

The first track mentor needs to be added manually by @kytrinyx, but after that there's a section in the account where existing track mentors can invite new ones.

The most successful tracks are where each submission receives feedback quickly, preferably within the first 24 hours.

In addition, the most interesting and useful conversations start when reviewers do not direct users to do specific things, but rather ask questions challenging people to think about different aspects of their solution, or explore aspects of the language.

Referencing existing blog posts and style guides seems to work well when making specific recommendations.

Prepare for Open Source Contributions

Once the track is live and active, it will often get new contributions.

• Read the maintainer documentation
• "Watch" the xperl6 repository
• Find a second maintainer

We've got a few years of experience maintaining language tracks on Exercism. Here's what we have learned:

• Maintaining a Track
• Reviewing a Pull Request

There's more stuff in the contributing guide, as well. We're working on turning that into better, more focused maintainer documentation.

Launch!

• Toggle "active" to true in config.json
• Mention it in the next "Behind the Scenes" newsletter (@kytrinyx)

Update config.json to match new specification

For the past three years, the ordering of exercises has been done based on gut feelings and wild guesses. As a result, the progression of the exercises has been somewhat haphazard.

In the past few months maintainers of several tracks have invested a great deal of time in analyzing what concepts various exercises require, and then reordering the tracks as a result of that analysis.

It would be useful to bake this data into the track configuration so that we can adjust it over time as we learn more about each exercise.

To this end, we've decided to add a new key exercises in the config.json file, and deprecate the problems key.

See exercism/discussions#60 for details about this decision.

Note that we will not be removing the problems key at this time, as this would break the website and a number of tools.

The process for deprecating the old problems array will be:

• Update all of the track configs to contain the new exercises key, with whatever data we have.
• Simultaneously change the website and tools to support both formats.
• Once all of the tracks have added the exercises key, remove support for the old key in the site and tools.
• Remove the old key from all of the track configs.

In the new format, each exercise is a JSON object with three properties:

• slug: the identifier of the exercise
• difficulty: a number from 1 to 10 where 1 is the easiest and 10 is the most difficult
• topics: an array of strings describing topics relevant to the exercise. We maintain
  a list of common topics at https://github.com/exercism/x-common/blob/master/TOPICS.txt. Do not feel like you need to restrict yourself to this list;
  it's only there so that we don't end up with 20 variations on the same topic. Each
  language is different, and there will likely be topics specific to each language that will
  not make it onto the list.

The difficulty rating can be a very rough estimate.

The topics array can be empty if this analysis has not yet been done.

Example:

"exercises": [
  {
    "slug": "hello-world" ,
    "difficulty": 1,
    "topics": [
        "control-flow (if-statements)",
        "optional values",
        "text formatting"
    ]
  },
  {
    "difficulty": 3,
    "slug": "anagram",
    "topics": [
        "strings",
        "filtering"
    ]
  },
  {
    "difficulty": 10,
    "slug": "forth",
    "topics": [
        "parsing",
        "transforming",
        "stacks"
    ]
  }
]

It may be worth making the change in several passes:

1. Add the exercises key with the array of objects, where difficulty is 1 and topics is empty.
2. Update the difficulty settings to reflect a more accurate guess.
3. Add topics (perhaps one-by-one, in separate pull requests, in order to have useful discussions about each exercise).

binary: improve tests for invalid numbers

We should have separate tests for:

• alphabetic characters at the beginning of a valid binary number
• alphabetic characters at the end of a valid binary number
• alphabetic characters in the middle of an otherwise valid binary number
• invalid digits (e.g. 2)

If the test suite for binary has test cases that cover these edge cases, this issue can safely be closed.

See exercism/problem-specifications#95

Where are the Perl 6 communities and enthusiasts?

As we move towards the launch of the new version of Exercism we are going to be ramping up on actively recruiting people to help provide feedback.

Our goal is to get to 100%: everyone who submits a solution and wants feedback should get feedback. Good feedback. You can read more about this aspect of the new site here: http://mentoring.exercism.io/

To do this, we're going to need a lot more information about where we can find language enthusiasts.

• Is Perl 6 supported by one or more large organizations?
• Does Perl 6 have an official community manager?
• Do you know of specific communities (online or offline) that are enthusiastic about Perl 6? (Chat communities, forums, meetups, student clubs, etc)
• Are there popular conferences for Perl 6? (If so, what are some examples?)
• Are there any organizations who are targeted specifically at getting certain subgroups or demographics interested in Perl 6? (e.g. kids, teenagers, career changers, people belonging to various groups that are typically underrepresented in tech?)
• Are there specific groups or programs dedicated to mentoring people in Perl 6?
• Are there popular newsletters for Perl 6?
• Is Perl 6 taught at programming bootcamps? (If so, what are some examples?)
• Is Perl 6 taught at universities? (If so, what are some examples?)

In other words: where do people care a lot and/or know a lot about Perl 6?

This is part of the project being tracked in exercism/meta#103

Verify that nothing links to help.exercism.io

The old help site was deprecated in December 2015. We now have content that is displayed on the main exercism.io website, under each individual language on http://exercism.io/languages.

The content itself is maintained along with the language track itself, under the docs/ directory.

We decided on this approach since the maintainers of each individual language track are in the best position to review documentation about the language itself or the language track on Exercism.

Please verify that nothing in docs/ refers to the help.exercism.io site. It should instead point to http://exercism.io/languages/:track_id (at the moment the various tabs are not linkable, unfortunately, we may need to reorganize the pages in order to fix that).

Also, some language tracks reference help.exercism.io in the SETUP.md file, which gets included into the README of every single exercise in the track.

We may also have referenced non-track-specific content that lived on help.exercism.io. This content has probably been migrated to the Contributing Guide of the x-common repository. If it has not been migrated, it would be a great help if you opened an issue in x-common so that we can remedy the situation. If possible, please link to the old article in the deprecated help repository.

If nothing in this repository references help.exercism.io, then this can safely be closed.

Create module files for exercises that already have the test file and module linked

All other languages I've used on Exercism include a readme, a test file, and a module that has the boilerplate code sketched out for you.

In order to make these ultra beginner friendly, the module files should be included.

As-is, a beginner like myself would have to go through a whole tutorial on how .t files work and how the module system works in order to just work on a challenge.

rna-transcription: don't transcribe both ways

I can't remember the history of this, but we ended up with a weird non-biological thing in the RNA transcription exercise, where some test suites also have tests for transcribing from RNA back to DNA. This makes no sense.

If this track does have tests for the reverse transcription, we should remove them, and also simplify the reference solution to match.

If this track doesn't have any tests for RNA->DNA transcription, then this issue can be closed.

See exercism/problem-specifications#148

Add key features

This issue is part of the migration to v3. You can read full details about the various changes here.

In Exercism v3, each track must specify exactly six "key features". Exercism uses these features to highlight the most interesting, unique or "best" features of a language to a student.

Key features are specified in the top-level "key_features" field in the track's config.json file and are defined as an array of objects, as specified in the spec.

Goal

The "key_features" field in the config.json file should be updated to describe the six "key features" of this track. See the spec.

Example

{
  "key_features": [
    {
      "icon": "features-oop",
      "title": "Modern",
      "content": "C# is a modern, fast-evolving language."
    },
    {
      "icon": "features-strongly-typed",
      "title": "Cross-platform",
      "content": "C# runs on almost any platform and chipset."
    },
    {
      "icon": "features-functional",
      "title": "Multi-paradigm",
      "content": "C# is primarily an object-oriented language, but also has lots of functional features."
    },
    {
      "icon": "features-lazy",
      "title": "General purpose",
      "content": "C# can be used for a wide variety of workloads, like websites, console applications, and even games."
    },
    {
      "icon": "features-declarative",
      "title": "Tooling",
      "content": "C# has excellent tooling, with linting and advanced refactoring options built-in."
    },
    {
      "icon": "features-generic",
      "title": "Documentation",
      "content": "Documentation is excellent and exhaustive, making it easy to get started with C#."
    }
  ]
}

Tracking

exercism/v3-launch#5

The test file for Hello World is overly confusing and can turn off newcomers

Compare Python's Hello World test file https://github.com/exercism/python/blob/master/exercises/hello-world/hello_world_test.py

To Perl 6's https://github.com/exercism/perl6/blob/master/exercises/hello-world/hello-world.t

Is there anyway to simplify Perl 6's testing files? Ideally, a test file that a student downloads would teach them how to set up a test. This file is sort of unreadable.

is hello, |.<expected description> for @($c-data<cases>);

In order to test in Perl 6, first you must learn the entire language? Kind of defeats the purpose of Perl allowing for "baby talk" as well as Shakespeare.

JSON::Fast required for Hello World

Is JSON::Fast really needed for testing hello world? If so, at least tell the user that they need to obtain it and explain how to do it (ie with zef).

How to set up a local dev environment

See issue exercism/exercism#2092 for an overview of operation welcome contributors.

---

Provide instructions on how to contribute patches to the exercism test suites
and examples: dependencies, running the tests, what gets tested on Travis-CI,
etc.

The contributing document
in the x-api repository describes how all the language tracks are put
together, as well as details about the common metadata, and high-level
information about contributing to existing problems, or adding new problems.

The README here should be language-specific, and can point to the contributing
guide for more context.

From the OpenHatch guide:

Here are common elements of setting up a development environment you’ll want your guide to address:

Preparing their computer
Make sure they’re familiar with their operating system’s tools, such as the terminal/command prompt. You can do this by linking to a tutorial and asking contributors to make sure they understand it. There are usually great tutorials already out there - OpenHatch’s command line tutorial can be found here.
If contributors need to set up a virtual environment, access a virtual machine, or download a specific development kit, give them instructions on how to do so.
List any dependencies needed to run your project, and how to install them. If there are good installation guides for those dependencies, link to them.

Downloading the source
Give detailed instructions on how to download the source of the project, including common missteps or obstacles.

How to view/test changes
Give instructions on how to view and test the changes they’ve made. This may vary depending on what they’ve changed, but do your best to cover common changes. This can be as simple as viewing an html document in a browser, but may be more complicated.

Installation will often differ depending on the operating system of the contributor. You will probably need to create separate instructions in various parts of your guide for Windows, Mac and Linux users. If you only want to support development on a single operating system, make sure that is clear to users, ideally in the top-level documentation.

[v3] Build Test Runner

This issue is part of the migration to v3. You can read full details about the various changes here.

In Exercism v3, one of the biggest changes is that we'll automatically check if a submitted solution passes all the tests.

We'll check this via a new, track-specific tool: the Test Runner. Each test runner is track-specific. When a new solution is submitted, we run the track's test runner, which outputs a JSON file that describes the test results.

The test runner must be able to run the tests suites of both Concept Exercises and Practice Exercises. Depending on the test runner implementation, this could mean having to update the Practice Exercises to the format expected by the test runner.

Goal

Build a test runner for your track according to the spec.

If you are building a test runner from scratch, we have a starting guide and a generic test runner that can be used as the base for the new test runner.

If a test runner has already been built for this track, please check if it works on both Concept Exercises and Practice Exercises.

It can be very useful to check how other tracks have implemented their test runner.

Tracking

exercism/v3-launch#4

Fix getting started instructions for perl6

Some exercise README templates contain links to pages which no longer exist in v2 Exercism.

For example, C++'s README template had a link to /languages/cpp for instructions on running tests. The correct URLs to use can be found in the 'Still stuck?' sidebar of exercise pages on the live site. You'll need to join the track and go to the first exercise to see them.

Please update any broken links in the 'config/exercise_readme.go.tmpl' file, and run 'configlet generate .' to generate new exercise READMEs with the fixes.

Instructions for generating READMEs with configlet can be found at:
https://github.com/exercism/docs/blob/master/language-tracks/exercises/anatomy/readmes.md#generating-a-readme

Instructions for installing configlet can be found at:
https://github.com/exercism/docs/blob/bc29a1884da6c401de6f3f211d03aabe53894318/language-tracks/launch/first-exercise.md#the-configlet-tool

Tracking exercism/exercism#4102

Name nucleobases, not nucleosides

The primary nucleobases are cytosine (DNA and RNA), guanine (DNA and RNA), adenine (DNA and RNA), thymine (DNA) and uracil (RNA), abbreviated as C, G, A, T, and U, respectively. Because A, G, C, and T appear in the DNA, these molecules are called DNA-bases; A, G, C, and U are called RNA-bases. - Wikipedia

In other words, we should rename the values in the RNA transcription problem to reflect the following:

• cytidine -> cytosine
• guanosine -> guanine
• adenosine -> adenine
• thymidine -> thymine
• uridine -> uracil

Move JSON into tests

It occurred to me that to be able to run some of the test suites properly, the user either must fetch the exercise themselves, or find the files from the repository.

There is a 'Test Suite' page on the Exercism site, but it is unusable if an exercise uses a separate JSON file e.g. http://exercism.io/exercises/perl6/atbash-cipher/test-suite