feature(#2290): Use a param value as the default value of other param

[jcagarcia]

Hey! 👋

I think the feature requested in #2290 is pretty interesting. So I've added this PR for allowing to use a param value as the default value of some other parameter.

So now, we can do:

params do
  optional :color, type: String, default: 'blue'
  optional :primary_color, type: String, default: -> (params) { params[:color] }
end

I've updated the README for including this new feature. Don't know if the next version should be 2.1.0 instead of 2.0.1. Let me know if I should change it.

Thanks!!

[dblock]

Very nice! Yes, let's make this 2.1.0 in this PR. Thanks.

[jcagarcia]

Thanks @dblock ! I've just updated the version to 2.1.0. Let me know if anything else is needed 👍

[dblock]

Stable release mentions 2.0.1 too, needs to be 2.1.0, thanks!

https://github.com/ruby-grape/grape#stable-release

[jcagarcia]

Sure! I've just commit the change for updating the stable release section :) Hope it helps!

[dblock]

One last thing, I promise that's it after that. We don't wrap text in markdown manually since it shows up, make this all 1-line.

[jcagarcia]

Hi @dblock ! Don't worry at all, I really appreciate the reviews :)

I've just updated my addition to the README file for following 1-line format. However, I did it in that way because all the other sections of the document.

As you can see here:

https://github.com/ruby-grape/grape/blob/master/README.md?plain=1#L153-L159

If the 1-line is the new convention you want to follow, do you think I can help on moving all the README to 1-line format?

[dblock]

Absolutely. Maybe we can find a linter to run in PRs too?

[jcagarcia]

Sure! Let me try to PR this :)

[dblock]

Merged, thanks for hanging in here with me!