Hi all!
I believe that any good technical book must have an index, but I can not find anything similar in the Language Guide and Language Reference. This is very frustrating because it makes them much harder to read and use as a reference. Is there any chance they get it eventually?
For the reference portion of the book, you can use the grammar summary as a sort of index. If you have a local copy of the ePub version, you could grep through it to find terms and such.
Otherwise, suggestions like yours are a good candidate for Feedback Assistant.
It's an epub or website aka a digital record. Apple's Books app could search an epub and Google could search a website. I don't think any digital records need an index as long as you could search the content of it.
I'd yet rather have an index, but it maybe I'm wrong.
You’re not wrong. A good-quality human-authored index is a very valuable tool. It’s also a lot of work. I’m going to reiterate Kyle Murray’s earlier advice: You should file an enhancement request for this.