Exercise generator

[bmulvihill]

Overview

Based on #20
Creates an basic exercise generator for the Crystal language track. The generator lives in the src directory. This generator is based on the ruby generator - but is not a complete copy. (Beware I am a Ruby dev, and have been getting into Crystal lately, so I have not completely learned all the Crystal best practices). I have created a sample generator for the hello-world exercise as an example.

Creating a new Generator

• Navigate to src/generator/exercises and create a new generator file (i.e. hello_world.cr).
• This file should contain 2 classes
  • An exercise generator which must inherit from the ExerciseGenerator class
  • A test case class which inherits from ExerciseTestCase.
• The x-common repo must reside at the same level as the developer's crystal directory, and must contain a canonical-data.json file for the given exercise.

Running the Generator

From within the xcrystal directory:

crystal src/generator/generate.cr hello-world

Or build a binary

make build_generator
bin/generate hello-world

Future Work/Issues

This is just an initial implementation and would like to keep this PR fairly focused on just getting a basic generator implemented.

Currently a lot of the test suites write the tested method is a describe block (i.e. describe "#hello"). I am not quite sure a clean way to implement this using the canonical data since it doesn't define the tested methods.

Let me know if you have any questions/concerns/comments!

[mhelmetag]

@bmulvihill , I'll look at this after work but I'm glad you reopened it! Looks cool! I would love to add pulling the raw json from x-common's github so we don't have to worry about having x-common locally or it being up to date (I have a branch out that does that so I can extend this after we merge this).

This is awesome!!

Currently a lot of the test suites write the tested method is a describe block (i.e. describe "#hello"). I am not quite sure a clean way to implement this using the canonical data since it doesn't define the tested methods.

I don't think this style of test case is absolutely necessary and the benefit of automated test cases is greater than the burden of not-perfectly-canonical-test-cases.

One thing that I would love to push towards is a unified generator for all exercises but... maybe there's too much variation between them.

[bmulvihill]

Thanks for taking a look!

I agree about the x-common problem, I just went with what we were doing on the Ruby repo for now since it is a simple solution.

I also agree a unified generator would be nice, but until the day where all the canonical data adheres to a the same signature/interface creating a simple TestCase class to handle the differences should work.

[mhelmetag]

I don't really have much to say about all this 😆 it looks pretty great!

[mhelmetag]

I usually like to use unless of if !. Just a nit...

[bmulvihill]

I agree, but I have a rebuttal in the case when an else statement is used, I think unless can be confusing, but I could change this to if name and switch the logic around.

[mhelmetag]

Ah, yeah. True... I do usually use unless by itself.

Thanks for the update though!

[mhelmetag]

So this is awesome. I think if you're happy with it I'll merge it in and get to working on pulling in the json from github and then knocking out some more exercises. Thanks a bunch again!