Thank you so much for adding a Crystal client generator! I got a little ambitious and attempted to generate a Stripe API client from their OAS3 definition. From inside that repo, I ran the following:

openapi-generator generate -i openapi/spec3.yaml -g crystal -p shardName=stripe -p moduleName=Stripe -o ../stripe

Then I spun up a new Crystal app:

• crystal init app test_stripe
• Added the generated Crystal shard as a dependency in shard.yml with path: ../stripe
• In my new app's src/test_stripe.cr:

  require "stripe"
  
  Stripe.configure do |c|
    c.api_key = ENV["STRIPE_API_KEY"]
  end
  
  pp Stripe.get_customers

• crystal src/test_stripe.cr

There were a few compiler errors for a Crystal project I spun up to test-drive it and I've gotten all the ones I found nailed down here. For the most part, it just looked like some method calls missed in copying over the Ruby generator. And then there were a couple syntax errors — a stray ] character and unescaped quotes in a string. Nothing major so far.

Unfortunately, I had trouble running the ./mvnw clean package command to check my changes or make sure I've caught everything. I'm getting never-ending exceptions in running it — it looks like the instrumentation to capture the exception is also raising exceptions. So I may need a little guidance there.

/cc @wing328

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  For Windows users, please run the script in Git BASH.
• File the PR against the correct branch: master, 5.1.x, 6.0.x
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.