Optional dependencies

[rickychilcott]

This PR provides a helper to "require" the gem into the project... but only if it's in already in the Gemfile, otherwise it raises a semi-helpful error message.

In order for this to work, the dependency still needs to be a development dependency (i.e. spec.add_development_dependency) in the gemspec

Works on #3

[rickychilcott]

@andreibondarev check this out. It's kinda cool. I think we could auto-require all development dependencies in the test environment, but there are pros and cons to that. Let me know if you think we should.

[andreibondarev]

@andreibondarev check this out. It's kinda cool. I think we could auto-require all development dependencies in the test environment, but there are pros and cons to that. Let me know if you think we should.

I think that is okay, yes.

[andreibondarev]

Do you think we should move ALL of the gems here or maybe leave some core ones under actual deps below?

[rickychilcott]

I'm not sure. Only the LLMs would feel core enough, but then again, why have cohere if you're using openai?

I could imagine actual core ones being activesupport or other similar gems needed for the plumbing of langchain.

So yes, but in its current state, there might not be any true dependences at all.

[andreibondarev]

The idea is that you can swap out different LLMs. Ideally, eventually, I think we ought to have a lot more LLM options to pick from.

[andreibondarev]

@rickychilcott Left you some feedback! THANK YOU for the contribution so far!

[rickychilcott]

I ended up calling the method depend_on, and it felt like the best name at this time. Also, I was unable to figure out how to "auto require" each of the gems in test because there can be a divergence between the gem name and the require statement. So those spec files that need to reference the underlying library will need to manually require.

I think this is ready for another review and a thumbs up if we're on the same page to apply this everywhere.

[andreibondarev]

@rickychilcott Would you please upmerge and resolve the conflict (Gemfile.lock I think) and I'll merge this PR in! Thanks again!

[rickychilcott]

Done!

[rickychilcott]

Cool! I'm happy to apply this pattern across the Readme and codebase in a separate PR. I might get an opportunity to do so later today or tomorrow.

[andreibondarev]

@rickychilcott Let's do it! I think the examples in examples/ might need to be updated as well. Or at least mention like:

# gem install "cohere-ruby"