Slides to use at FR ropp-study
Examples
* Validator
http://bit.ly/2mVPIpx
* Throw an error when accessing unknown property
http://bit.ly/2zwpaB2
* Negative index for Array
http://bit.ly/2iJ5W0u
* Immutability
http://bit.ly/2hKxp14
Measurement script: http://bit.ly/2hZnBEa