so suppose you're a client and you buy chromatic's book. it's a draft ! it does not describe a product....
You are more than welcome to test everything in the upcoming Rakudo Perl 6 book against the monthly Rakudo releases or any revision of Rakudo. If you find a bug, please report it. We will fix it. The book is the second highest priority after releasing Rakudo Star in the next couple of months.
Every example not explicitly labeled as "experimental" will work (barring typos, which we hope to avoid) with Rakudo Star. The book will come out approximately the same time as Rakudo Star (I can't predict to the day how long it will take at the printer).
The plan for the book is to cover only those features in which we have supreme confidence that they will remain unchanged through the lifetime of Perl 6.0. I don't think even Larry himself would sign a paper guaranteeing that, but we have high confidence in them.