vagrant

https://github.com/mitchellh/vagrant

Ruby

Vagrant is a tool for building and distributing development environments.

Vagrant::Plugin::V2::Config#merge

Merge another configuration object into this one. This assumes that
the other object is the same class as this one. This should not
mutate this object, but instead should return a new, merged object.

The default implementation will simply iterate over the instance
variables and merge them together, with this object overriding
any conflicting instance variables of the older object. Instance
variables starting with "__" (double underscores) will be ignored.
This lets you set some sort of instance-specific state on your
configuration keys without them being merged together later.

Source | Google | Stack overflow

Edit

git clone [email protected]:mitchellh/vagrant.git

cd vagrant

open lib/vagrant/plugin/v2/config.rb

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-Vagrant--Plugin--V2--Config-merge-for-pr

# Commit to git

git add lib/vagrant/plugin/v2/config.rbgit commit -m "better docs for Vagrant::Plugin::V2::Config#merge"

# Open pull request

gem install hub # on a mac you can `brew install hub`

hub fork

git push <your name> -your-name--update-docs-Vagrant--Plugin--V2--Config-merge-for-pr

hub pull-request

# Celebrate!