sonic-pi

https://github.com/sonic-pi-net/sonic-pi

C++

Code. Music. Live.

#prettify

This example demonstrates tree error reporting in a real life example. 
The parser code has been contributed by John Mettraux.

Source | Google | Stack overflow

Edit

git clone [email protected]:sonic-pi-net/sonic-pi.git
cd sonic-pi
open app/server/ruby/vendor/parslet/example/nested_errors.rb

Contribute

# Make a new branch
git checkout -b -your-name--update-docs--prettify-for-pr

# Commit to git
git add app/server/ruby/vendor/parslet/example/nested_errors.rbgit commit -m "better docs for #prettify"

# Open pull request
gem install hub # on a mac you can `brew install hub`
hub fork
git push <your name> -your-name--update-docs--prettify-for-pr
hub pull-request

# Celebrate!