childprocess

https://github.com/enkessler/childprocess

Ruby

Cross-platform Ruby library for managing child processes.

Observable#add_observer

Add +observer+ as an observer on this object. so that it will receive
notifications.

+observer+:: the object that will be notified of changes.
+func+:: Symbol naming the method that will be called when this Observable
         has changes.

         This method must return true for +observer.respond_to?+ and will
         receive <tt>*arg</tt> when #notify_observers is called, where
         <tt>*arg</tt> is the value passed to #notify_observers by this
         Observable

Source | Google | Stack overflow

Edit

git clone [email protected]:enkessler/childprocess.git
cd childprocess
open

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-Observable-add_observer-for-pr

# Commit to git

git add git commit -m "better docs for Observable#add_observer"

# Open pull request

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

hub fork

git push <your name> -your-name--update-docs-Observable-add_observer-for-pr

hub pull-request

# Celebrate!